I know this isn’t entomological in the strict sense, but isn’t it just grand when you come upon an arthropod as splendid as this freshly-moulted Phidippus johnsoni? What a beautiful spider! I found this last evening in Mt. Tolmie Park in Victoria, BC, and you can be sure where beauties like this are turning up, a plethora of insects also awaits. I can’t wait to go and explore!
This wasp has a problem! Three relatively enormous parasitic strepsipterans are occupying her abdomen…Photo by Sean McCann.
Who wouldn’t want to get to know the Strepsiptera? These animals are extremely odd, being obligate endoparasites of other insects, with a free-flying male and an eyeless, wingless female that never leaves the abdomen of her host. Different families of these parasites infect different hosts, ranging from silverfish and cockroaches to solitary and social wasps, leafhoppers, and froghoppers.
Allow me to introduce Xenos peckii, a strepsipteran parasite of Polistes fuscatus, the Northern Paper Wasp. As an entomologist, I have long been interested in these little-studied insects, so I was thrilled to get to help my colleague Mike Hrabar in his investigation their life history and reproduction.
Mike collected a several colonies of infected wasps from Maine and brought them back to the lab to observe their emergence, flight and mating behaviour in a systematic way. We used high speed videography and careful record keeping to document their life history in closer detail than had ever previously been recorded.
Not really bling. This wasp sports a heavy infestation of four developing Xenos, costing vast amounts of resources. Photo by Sean McCann.
From my perspective, one of the coolest things we learned is that the free-flying male opens his puparium by means of blade-like mandibles, which are used to cut along a zone of weakness in the pupal cap, functioning like a tiny can opener!
Head of male Xenos peckii. Note the scissor-like mandibles and the large and unusual compound eyes. Photo by Mike Hrabar. Figure 3G from Hrabar et al. 2014.
Check out the video below to see the male’s little mandibles working the cap open.
[youtube http://www.youtube.com/watch?v=aCeEsXVNiOY?rel=0&w=560&h=315]
These little troopers fly immediately upon emergence, in stark contrast with most other insects, which need time to inflate and harden their wings. In fact, once the males begin beating their wings, they remain in flight continuously except for a brief period during mating.
Before our study, biologists had assumed that female Strepsiptera were completely immobile and passively waited for males to find them, but we observed that they move to adopt a distinct calling posture, elevating their cephalothorax up from the wasp’s abdomen, likely emitting a pheromone plume.
Female Xenos peckii in the abdomen of a Polistes fuscatus. This female is in the calling posture, elevating her cephalothorax. Photo by Mike Hrabar. Figure 4D from Hrabar et al. 2014.
The males smell this pheromone plume and fly toward it rapidly, in a zig-zag fashion reminiscent of pheromone-questing moths. As soon as a male reaches the female-infected host, he lands on her abdomen and walks down to where the female protrudes, using backwards steps with his heavily-modified tarsi.
Mid leg of Xenos peckii male. The tarsi are highly modified for gaining a strong grip on a wasp abdomen while searching for and mating with a female. Figure 8 from Hrabar et al. 2014.
Mating occurs rapidly, with typical copulation time being 3-5 seconds. As soon as mating is finished, the male is once again in flight, presumably in search of another female. After copulation, the female immediately withdraws from the calling posture and ceases calling other males. The following video was taken at 1000 frames/second with a high-speed video camera and shows the sequence from just after landing by the male through the majority of copulation.
[youtube http://www.youtube.com/watch?v=QPiG8AV0XWY?rel=0&w=560&h=420]
This male Polistes fuscatus was weakening, and died while we were watching. Mike pinned the host, and we forgot about it for a while, until glancing at it we realized that one of the males was emerging! This shot was snatched quickly while the male had just popped off his cephalotheca. Photo by Sean McCann, Figure 2E from Hrabar et al. 2014.
We have shown that female Xenos are not just a passive receptacle or bag of eggs, but rather play a physically active role in soliciting mates. The male emergence is facilitated by using sharp mandibles to cut around an ecdysial suture line, and navigating the surface of his prospective mates host is aided by his extremely modified tarsi.
The short-lived males face a great challenge to locate and fly to a host with a calling female in the short amount of time they live (on average 2-2.5 hours). They are in constant flight from emergence until death with only a very short pause for mating. The female, by contrast, remains alive in her host, maturing a brood of eggs which she retains in her body until they hatch and crawl from her brood canal as motile planidial larvae.
These larvae will exit the brood canal at some point, but it is unclear exactly where they manage to find new hosts. It is possible they “deplane” at flowers and wait for a ride on a Polistes to a new nest of victims. Much more research will need to happen to fully understand these fascinating insects, but we have made a start at uncovering some of the mysteries of their emergence, communication and reproduction. Many more questions remain unanswered and provide opportunities for any natural historian to explore.
If you would like to read the whole paper, you can find it on the Canadian Entomologist site here, or if you are not a subscriber, I am hosting a corrected proof here.
The full citation for this paper is:
HRABAR, M., DANCI, A., MCCANN, S., SCHAEFER, P. W., and GRIES, G. 2014. New findings on life history traits of Xenos peckii (Strepsiptera: Xenidae). The Canadian Entomologist doi: http://dx.doi.org/10.4039/tce.2013.85 pp.1–14.
While out visiting our friend Rafael’s ranchito yesterday, we were surrounded by a herd of curious cattle. These were a mix of both Brahmas and Holsteins, with some crosses as well. One animal in particular caught my eye; it appeared to have bot emergence holes on its sides.
I asked Rafael what these were, and sure enough, he told me that these were “torsalo”, basically the same New World bot that scientists are always getting in the Neotropics. I was not aware that Dermatobia hominis parasitizes cattle, but apparently it quite commonly does so. It makes sense, as emergence sites of Cattle Grubs would be higher up on the back of the animal.
I love it how my entomological training really gets awakened when travelling in new areas.
I am sure many folks out there know what it is like to rent their very first apartment, only to find that the place has a major infestation of some noxious pest. Well, fellow ESC member Catherine Scott and I have just rented our first apartment in Gualaco, Honduras, and boy does it ever have an infestation!
These are the dreaded household casebearer, Phereoeca uterella (Tineidae), and there are tons of the wandering larvae all over the walls! Luckily we have other familiar allies, the Pholcids, which are in great abundance. This infestation will be easy to manage provided we take care of the moths’ food sources. This is definitely not the worst infestation I have experienced.
Allies in the fight against clothes moths!
Anyway, these are the most obvious insects in our new home. Please share below about any experiences with first-apartment infestations you may have had!
By Sean McCann, ESC/SEC blog coordinator and PhD student at Simon Fraser University —— 
It seems that a popular pastime for Canadian entomologists in winter is to reminisce about warmer times and abundant insects. Edmonton bug photographer Adrian Thysse just posted a video of his National Moth Week experience at Devonian Gardens in Edmonton over the summer, and it looks like an entomological wonderland compared to the insect famine that is the Canadian winter. That video reminded me of my own light trapping experiences in much warmer times, namely in the rainforest of French Guiana. I was not actually doing the trapping, but I had the good fortune to do some observation. Guelph’s own Alex Smith and Rodolphe Rougerie were using UV lamps and white sheets to do their sampling, but of course all kinds of amazing insects were coming to the sheets. If you have never experienced tropical light trapping, the video below provides a taste of the sheer biomass of insects coming to a single sheet. [flickr video=11200757316 secret=7ec05d78b3 w=560 h=315] Here is a small gallery of images of insects that caught my eye (bonus points if you can ID them in the comments!).
Human hangers-on were not the only beneficiaries of this insect bonanza. Under the sheet, toads gathered to feast, while bats swooped in from above. The next morning, the diurnal predators took over, with scores of birds waiting above to snatch the tasty morsels from the air as they tried to fly back to their homes in the trees. Here a Black Nunbird (Monasa atra) shows up on a perch with a gift. [flickr video=11200587055 secret=bdf1a44633 w=560 h=315] This gift-giving was a bit of a theme, with a Black-bellied Cuckoo offering a large katydid to an associate. 
For an entomologist who studies birds such as myself, the light traps were a wonderful thing to see. Waking up at dawn to see a concentrated slice of bird-insect interaction in the warmth of the tropical rainforest is something I will never forget. As the winter tightens its grip on Canada, its insects, and those who study them, I hope this post helps warm you up!
By David McCorquodale, Dean of Science and Technology, Cape Breton University
There is a perception that Nova Scotia and Cape Breton (where I live) may be subject to an invasion of cicadas. The perception seems to stem from the mass emergence of cicadas in the northeastern USA this spring and summer. What an opportunity to build suspense and stress! Consider this headline from Design and Trend on 09 May 2013: CICADAPOCALYPSE: Mass Exodus from the Ground. A Google search revealed dozens of similar, but admittedly not as sensationalist, headlines from news outlets in the northeastern US and a few in Canada.
In my 35 years as an entomologist in Canada I have seen, heard and collected many cicadas. The delightful Dog Day Cicada (Tibicen canicularis) sings from the White Birch trees near my house every summer. It is the species I have seen and heard most frequently. Cicadas are big (some more than 30 mm long, all at least 20 mm long), loud (at least to those who have not lost their high end hearing) and widely distributed across southern Canada. Sound production is fascinating. Males have tymbals under their wings. Tymbals have taut membranes across an echo chamber. The membranes vibrate to produce the high pitched, incessant, droning calls on hot summer days.
Tibicen canicularis. Photo by Denis Doucet
However I suspect many people have never seen or knowingly heard cicadas. Why? Probably because most of their life is spent as larvae underground sucking liquids out of roots so they can grow, mature and emerge as adults. Males sing from tree tops, mate with females who then lay eggs on twigs, when the eggs hatch the larvae fall to the ground and burrow to feed on roots. The larvae burrow down among the roots, not to be seem until they emerge as adults.
How can we reconcile these disparate pieces of information: i) cicadas are common and widespread where Canadians live, ii) most people have never seen them and iii) WARNING mass invasion of cicadas this summer!
We cannot because there will not be a mass emergence in Nova Scotia or indeed in eastern Canada. There will be about the same number of adult cicadas in eastern Canada as in any other year. No one will be able to detect a difference in the number of cicadas in 2013 compared to previous years. Perhaps there will be more attention on cicadas — that is a good thing.
How can I say this and go against all the headlines? The first step is to consider what species of cicadas occur in eastern Canada and compare that to which species of cicadas have mass emergences. In Nova Scotia there are three species of cicadas. All three are ‘annual’ cicadas. That is adults emerge each year, mate, lay eggs, larvae develop and then the adults emerge the next year. There are not dramatic differences in the number of adults from year to year. Males sing form the treetops every year and most year most people are blissfully ignorant they are there.
However in the eastern USA there are several species of cicadas (Periodical Cicadas, Magicacada spp.) with a different life cycle. These cicadas also have males who sing, females who mate and then lay eggs on twigs and larvae who feed on roots. But the next step is different, they keep feeding and do not emerge as adults for 13 or 17 years. The adults that emerge are ‘teenagers’, not one year olds. Some periodical cicadas emerge every year, but some years, including 2013 in the eastern USA, there are enormous cohorts of adults that emerge. The timing, evolution and distribution of these periodical cicadas are fascinating (see Magicicada Mapping Project Homepage http://www.magicicada.org/map_project/maps.php, A National Geographic Project).
Legitimately, these intriguing insects are attracting lots of attention. Because many people have a fear (unrealistic in my opinion) of such a large insects there has been undue media attention to the mass emergence, the sensationalist headlines and unfounded stress in some people.
In Nova Scotia there are no reasonable ground to be concerned about a mass emergence of cicadas this summer. The three species of cicadas in Nova Scotia all have an annual life cycle. Numbers of adults that emerge each year are similar. We will not be able to see any difference in populations of adults this year compared to other years.
Despite being able to ally the concerns of Nova Scotians, I feel I am missing a spectacular natural phenomenon. Perhaps this is a reason to relocate from my Cape Breton home? A good one, but there are lots of good entomological reasons to stay.
For more information on cicadas, check out www.bugguide.org (search for cicada) and a paper published earlier in 2013: Biogeography of the Cicadas (Hemiptera: Cicadidae) of North America, North of Mexico by Allen F. Sanborn and Polly K. Phillips in Diversity 5: 166-239; doi:10.3390/d5020166.
By Mark P. Nelder, Public Health Ontario
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William R Maples’ Dead Men Do Tell Tales: The Strange and Fascinating Cases of a Forensic Anthropologist, created a lasting memory for me. Aside from the fascinating science, Dead Men Do Tell Tales underscored that passion and resourcefulness is the key to learning.
With an interest in blowfly ecology and ectoparasites, I set out to study these two fields as side projects during my graduate research at University of South Alabama (MSc) and Clemson University (PhD). Yes, “side projects” is a phrase that can send any supervisor running in fear, but I was lucky.
During my research on black fly larvae and their gut fungi in Alabama, I initially thought that the undersides of bridges (easiest place to look for streams and black flies; #overlyhonestmethods) are where headless white-tailed deer went to die. These morbid scenes of poaching were both a source of amazement and one of convenience – easily accessed streams with black fly larvae accompanied by robust populations of blowflies and louse flies (my first sight of the very cool Lipoptena mazamae). These deer were just a gateway carcass, leading to a downward spiral of seeking out additional species of dead wildlife and their ectoparasites. I was now a roadkill prospector.
Realizing that I needed experience with ectoparasites, prior to starting research on biting flies and ectoparasites of South Carolina zoos, I turned to the sometimes flattened, bloated, and unrecognizable critters I saw on my daily drive to campus. Equipped with latest intelligence on a fresh carcass, all I needed was a garbage bag, latex gloves, and a vehicle.
Roads pose a real threat to animal populations. The numbers are staggering, as reported by @TetZoo or Darren Naish in Dead Animals at the Roadside. In Belgium, an estimated 230,000 and 350,000 hedgehogs fall victim to vehicles per year. Not exploring this biodiversity source would constitute a wasted opportunity.
Insects and roads do not mix either. In Japan, a study of two routes resulted in 5000 dead insects per kilometer, collections dominated by Coleoptera, Lepidoptera, and Diptera (Yamada et al. 2010).
Roadkill are ideal subjects for biodiversity studies (the vertebrate hosts, along with their ectoparasites and internal parasites). As One Health opens the doors to collaboration between the fields of human medicine, veterinary medicine, and the environment, scientists often remain confined in their respective silos. Roadkill offers a potentially important source of data on zoonoses and generate collaboration between veterinarians, entomologists, microbiologists, ecologists, and others.
Interest in roadkill science is about as old as the automobile, albeit slower wildlife succumbed to horse drawn carriages of the 1800s. AW Schorger had more than a passing interest in roadkill, identifying 64 species of birds from 1932 to 1950, on the same roads between Madison, Wisconsin and Freeport, Illinois. Avian roadkill was dominated by English (House) Sparrows (N = 2784), Red-headed Woodpeckers (389), American Robins (310), Ring-necked Pheasants (271), Screech Owls (235), and Northern Flickers (230). Imagine the possible research if Schorger had a curious entomologist to tag along on these trips and to inspect each bird.
Transportation ecology is a relatively new field that looks to study how wildlife interacts with our roads and how road design can minimize wildlife impact. The University of California Davis and partners have established a citizen-science project that allows the public to report roadkill on California highways, California Roadkill Observation System (see Maine and Idaho). Championed by the Toronto Zoo, the Ontario Road Ecology Group looks to combat the impact of roads on biodiversity in southern Ontario. Yet another is the South African initiative Wildlife Road Traffic Accidents – A Biodiversity Research Project. These programs offer an existing infrastructure that provides the basis for longitudinal studies of ectoparasites and their hosts.
Aside from the basic understanding of host-ectoparasite relationships, roadkill are increasingly becoming a tool for hypothesis testing. A few examples are worth mentioning here. The Cardiff University Otter Project provided road-killed otters to test hypotheses surrounding otters, ticks, and climate. The prevalence, but not intensity, of the tick Ixodes hexagonus infestation on otters was associated with higher Central England temperatures, while both prevalence and intensity were associated with positive phases of the North Atlantic Oscillation.
Without roadkill, we would not know that as lice burden increases in barn owls, the number of pectinate claw teeth decreases and bill hook length increases (Bush et al. 2012). Bush and colleagues also noted rodent ectoparasites on barn owls; e.g., the louse Hoplopleura acanthopus (normally found on rats) and the flea Malaraeus telchinus (from mice and voles). Is this a potential example of incipient evolution through host switching?
Roadkill prospecting excited me (and still does)….not unlike an unexplored stream has excited many a black fly expert, as an illuminated cloth at night for the moth lover, and as CDC light trap the mosquito ecologist. As Dr. Diane Kelly said in her excellent Story Collider tale Confronting Death on the Road
When you open up an animal, there is all kinds of awesome in there.
By Sean McCann, PhD Canidate in Biological Sciences at Simon Fraser University
9/10 ant-mimicking mantids recommend tropical fieldwork for prevention of insect withdrawal. (Photo: S. McCann)
At this stage of the long dark Canadian winter, thoughts of tropical fieldwork should be going through the heads of all sensible entomologists…If you find yourself longing for the moist and insect-filled paradise of the Neotropics, or even if that is what your research plans call for, let me introduce you to the wonders of French Guiana.
Topography near the Inselberg Camp. (Photo: S. McCann)
French Guiana is situated just north of Brazil on the Atlantic coast of South America, and remains to this day an overseas Department of France. Both French and Creole are spoken, so Canadians should feel right at home.
French Guiana truly shines as a biodiversity and natural areas hotspot because unlike many countries in the Amazonian forest region, it has not experienced extensive deforestation. The immense expanses of unlogged rainforest are truly impressive.
The Inselberg des Nourages on a clear day. View not guaranteed, depends on the season. (Photo: S. McCann)
There is quite active citizen science in Guyane as well, of particular interest is the SEAG, or Société Entomologique Antilles Guyane: http://insectafgseag.myspecies.info/. This society has conducted numerous expeditions focused on collection and identification of many insect taxa, and represents a great resource of local knowledge of the insect fauna.
Finding a cryptic owlfly nymph is always a nice surprise (unless you are a cricket) (Photo: S. McCann)
I have done all my tropical fieldwork at the Nouragues station, supported by an annual grant program that seeks to assist visiting scientists with the travel and logistical expenses involved with a tropical field season. My work has centred on a bird which is a specialist predator of social wasps, the Red-throated Caracara.
Red-throated Caracaras are specialist predators of social wasps, and a common resident of the Nouragues Reserve. (Photo: S. McCann)
The 1000 km 2 Nouragues reserve is located approximately 100 km SSW of Cayenne, and was established in 1995 to be both a refuge free of development and to facilitate research on Neotropical forest dynamics.
Army ants (Eciton spp.) are one of the wonders of the Neotropical raindforests. Go. See. Them. (Photo: S. McCann)
There are two research camps, the Inselberg Camp, situated just beneath a 420 m granite mountain, the Inselberg des Nouragues, and the camp at Saut Pararé, situated just below a series of high rapids on the Arataye River. The camps are accessible by helicopter, or you can take a motorized canoe (pirogue) to the Saut Pararé camp. Both camps are administered by the CNRS (Centre Nationale de Recherche Scientifique) which has an office in Cayenne. Field costs are €20/day for students and postdocs and €35 per day for established researchers. Travel to the station can be expensive, but sharing the cost of helicopters/pirogues with other researchers can bring the costs down considerably.
Access to various parts of the forest is facilitated by an extensive trail system . Data on tree species and flowering/fruiting phenology in two large research plots at the Inselberg Camp are available. At the Pararé camp, there are also many trails, although not as extensive as at the Inselberg camp, as well as access to riverine and palm swamp habitats. Lists of species of birds, bats, fish and trees are available, and there is an impressive list of scientific data already published: http://www.nouragues.cnrs.fr/F-publications.html.
UV lamps attract a nice variety of insects. These are particularly fabulous. Start your collection today! (Photo: S. McCann)
The camps are comfortable, with covered shelters (carbets) for sleeping and eating, and there is electricity and running water at each station (it is the rainforest!). There is also a satellite internet connection which is adequate for email and keeping in touch with labs and colleagues. Food is provided, and is quite good (as one might expect at a French field station!), cooking/cleaning duties are shared.
The kitchen carbet by moonlight. (Photo: S. McCann)
If you are a student or a researcher at the planning or pre-planning stages of a Neotropical research program, there is no better time than now to submit a research proposal to the scientific committee of the station. The recently announced call for proposals will fund projects to a maximum of €9000, which would nicely cover the transportation and field costs for a several-month expedition. The deadline is Feb. 14, 2013. For more information, the details are available here: http://www.nouragues.cnrs.fr/indexenglish.html
One of the fringe benefits of running the ESC/ESAB JAM 2012 photo competition was getting a glimpse into what other people where interested in. One of the most unusual images we received was submitted by Marilyn Light, entitled “Trialeurodes sp.”.
Trialeurodes sp. with impostor…
The photomicrograph (a focus-stacked image, produced with Zerene Stacker) shows a fourth stage whitefly pupa case. Whitefly are hemipteran herbivores that are often found feeding on the underside of leaves.The species we know most about is the greenhouse whitefly (Trialeurodes vaporariorum), a pest that damages food crops by feeding on them and by spreading viruses. To control whitefly, growers resort to using the wasp Encarsia formosa. In this photograph we see a species of whitefly that was found on a wild orchid, the showy lady’s slipper (Cypripedium reginae Walter). The glassy spines are typical of some whitefly pupa, but what is amazing about this picture is that the creature inside is not a whitefly. Looking closer at the lower left of the image you can see the brownish-orange eyes of the head of a parasitoid wasp, with the thorax and abdomen almost filling the case. Marilyn has included the following information with the image:
from Wikipedia
The showy lady’s slipper orchid, Cypripedium reginae Walter, forms large colonies in fen wetlands. The insect herbivore assemblage of this orchid includes Trialeurodes sp. Cockerell (Hemiptera: Sternorrhyncha: Aleyrodidae) which was first observed by us in 2009 on orchids growing in stressed habitat. Eric Maw, CNC, determined this whitefly to be an undescribed Trialeurodes. Subsequently, we have found isolated infestations in a second orchid population which is less subject to drought stress. The whitefly is parasitized by Encarsia sp. Förster (Hymenoptera: Chalcidoidea: Aphelinidae). During microscopic examination of one 4 th stage nymph (pupa) case that had been removed from a freshly collected orchid leaf on September 22, 2012, I photographed a parasitoid that was soon to emerge. About half of the other cases examined had been parasitized.
Of course, being who I am, I was curious not only about the image, but also about the person who took it. I asked Marilyn to tell me a bit about herself and how the image came to be…
“I am a member of the ESC but do not earn my living through entomology. I am retired from the University of Ottawa Professional Training Service.
My interest in insect population dynamics begins with my experience in 1948-49 during an eastern tent caterpillar outbreak in Montreal: I was 7 years old. My dad showed me the the stages and how to distinguish male and female moths. My first teaching opportunity was with my Grade 2 classmates on the insect and its life history. Ever since I have been learning so I can teach others. In 1951, after the outbreak was subsiding, I observed a large caterpillar walking alone on a twig. It burst when touched, exuding pink fluid. I was to later learn that it had been infected with a virus. I remain fascinated by the delicate balance in nature, between plants and herbivores, and between herbivores, their pests and diseases.
My husband and I have been tracking wild orchid populations since 1985, examining how they are impacted by climatic variables, disturbance, pollinator behaviour, and insect herbivores. The dynamic of insect herbivore populations with their respective biological controls and the orchids is a natural extension of the work.
There is a paucity of information about insect biology except with species of economic importance or conservation value. Our investigations will hopefully serve to fill this gap. We publish regularly in both peer-reviewed and popular media.”
Professional work by dedicated ‘amateurs’! More of Marilyn’s work can be seen in the study, Potential impact of insect herbivores on orchid conservation. (Light, M. H. S. and MacConaill, M., 2011. European Journal of Environmental Sciences: Vol. 1, No. 2, pp. 115–124) and Possible Consequences of Walking off the Trail (Light, M. H. S., and M. MacConaill, 2008. Orchids: 77: pp 128-133). She is well known in the orchid community in Canada and abroad, and is author of the book, Growing Orchids in the Caribbean (Macmillan Caribbean, 1995).
By Laura Timms, Postdoctoral Researcher (McGill University), Chair of ESC Common Names Committee
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I’ve just come back from a weekend at my parents’ house, celebrating my Dad’s birthday and enjoying the beautiful early summer weather. My parents live on the Oak Ridges Moraine in Ontario – they have a gorgeous piece of property they’ve named Hawksview because of the panoramic vistas you get from on top of a large pile of old glacier scrapings.
View from my parents’ house – on clear days you can see all the way to Lake Ontario. Photo: Kathleen Timms
Coming from my shamefully barren urban yard, I am always amazed at the diversity of insect life on my parents’ property. Saturday morning I went outside with a cup of coffee to sit and enjoy the gardens, and within minutes was amazed at the amount of flower visiting taking place in front of me. I did a quick and unscientific count and came up with at least four species of big bees, six species of butterfly and who knows how many smaller flies and sundries buzzing in and out of the Weigela, Salvia, and Allium flowers.
My husband has done research on Bayesian learning in bumblebee foraging, and so the two of us often get caught up in watching bees drink nectar and thinking about their decision-making. As we were doing so this time, he noticed that one of the bee species was acting as a nectar robber – in other words, it was cutting a hole in the bottom of the flower and drinking the nectar through this hole instead of entering the flower in the usual way.
A carpenter bee, Xylocopa virginica, sitting on a Weigela flower and taking nectar through a hole it has cut in the base of the corolla. Photo: Laura Timms
This kind of interaction is referred to as nectar robbing because the bee is getting what it is after – the nectar – without paying the price of taking pollen along with it to the next bloom. Nectar robbing is often used as an example of how a mutualism like pollination, where both parties are supposed to benefit, can be subject to cheating. Charles Darwin speculated on the harm that nectar robbing must cause to plant fitness in his book The effects of cross and self-fertilisation in the vegetable kingdom (1877). I have to admit I didn’t know much about nectar robbing beyond the basics, and I also didn’t know what the species of bee was doing the robbing. A quick online search gave me answers on both counts.
The bee had a big, shiny black abdomen and a black spot on a fuzzy yellow thorax – had to be the eastern carpenter bee, Xylocopa virginica. It turns out carpenter bees are among the most common nectar robbers out there – they have short tongues, and can’t reach the nectar in flowers with long corollas, like my mother’s Weigela. But, it also turns out that nectar robbing isn’t necessarily always cheating, and may not be bad for the plant. Maloof and Inouye (2000) reviewed the literature on nectar robbing and found that there was more evidence for positive or neutral effects of nectar robbing on plant fitness than for negative effects. This is because other pollinators may still visit robbed flowers, some nectar robbers do actually pollinate, and nectar robbing can actually result in greater amounts of pollen flow between different plants and thus increase outcrossing. Fascinating!
I passed on this information to my parents, and resumed my garden sitting and coffee drinking. My attention was soon diverted again, this time by a bright red beetle on my Mom’s lilies. I didn’t need the internet to identify this beetle – it is an old friend of mine from when I worked in Switzerland at the Commonwealth Agricultural Bureau International. The lily leaf beetle, Lilioceris lilii, is an invasive species in North America and a voracious consumer of lilies. While the adult beetles are quite attractive the larvae have the gross habit of carrying around their frass on their backs, using it as a shield to deter predators and parasitoids (which is not always effective – see Schaffner and Müller 2001 for example).
A lily leaf beetle, Lilioceris lilii, surveys the garden. Photo: C. Ernst
I started scanning the lilies for beetles and larvae and removing them by hand – by far the best control method for a home gardener. I started squishing beetles and tossing them aside, when I remembered a recent email from a graduate student at the Université de Montréal. Alessandro Dieni is a student in Jacques Brodeur’s lab, and his research involves reconstructing the path of invasion of the lily leaf beetle using population genetics. Alessandro is looking for samples of the beetle from all over North America for his analysis, and so I stopped throwing the beetles away and started putting them in a jar of rubbing alcohol – the best collecting supplies I had on hand. I included the larvae too, after removing their fecal shields (for which my Mom made me wash my hands outside before coming in the house). It turns out that Alessandro can only use adults for his analysis, so the larvae aren’t much help. If you have lilies and have noticed these beetles in your garden, Alessandro would appreciate samples of adult beetles. You can contact him at alessandro.dieni-lafrance@umontreal.ca, and he will send you all the information you need, including a kit for collecting and preserving them.
One of the side effects of being an entomologist is being frequently asked the question: “What is this on my plant?” My dad asked me a few weeks ago about some galls he had noticed an oak tree, but I told him I couldn’t help him much without seeing them. So, one of my final tasks of the weekend was to check out the tree. This is what I saw:
Galls on a red oak, Quercus rubra, tree. Most are at the base of a branch. Some of the galls have had lots of adults emerge (note the emergence holes), and some have not. Photo: Laura Timms
My basic knowledge of oak galls told me that these galls were probably caused by cynipid wasps, but I wasn’t sure. We cut one open, and sure enough there was an almost fully developed wasp inside a chamber. Gall wasps lay their eggs in plant tissue, and the presence of the eggs induces the plant to produce the special types of highly nutritious cells that make up the gall. Larvae feed in chambers inside the gall, pupate, and then emerge out of small holes like the ones in the picture. I haven’t gotten very far with the identification of exactly which species of wasp is affecting my parents’ tree, although I’ve promised to look into it further and let them know if their tree is in serious trouble. I’m also curious to know if there are any other species inside the gall – oak galls are a fascinating system for work in community ecology, with a cast of cynipid wasps, parasitoids, predators and inquilines (e.g. Stone et al. 2002).
I’ve always said that my parents’ place would be a great field station. I’ve only mentioned three of the ecological tidbits that caught my eye this weekend, but I could go on about the way that dog-strangling vine is taking over the meadow and forest floor, our observations of caterpillars brought to the nest by purple martins, or the cool moths that show up at night by the outside lights. For the sake of brevity, I think those will all have to wait. In the mean time, now that my weekend entomology is over, I’m going to return to my regularly scheduled entomology and hit the microscope!
Literature cited
Darwin, C. 1877. The effects of cross and self fertilisation in the vegetable kingdom. D. Appleton and Co., New York.
Maloof, J.E., & Inouye, D.W. (2000). Are nectar robbers cheaters or mutualists? Ecology, 81, 2651-2661 DOI: 10.2307/177331
Schaffner, U., & Müller. C. (2001). Exploitation of the Fecal Shield of the Lily Leaf Beetle, Lilioceris lilii (Coleoptera: Chrysomelidae), by the Specialist Parasitoid Lemophagus pulcher (Hymenoptera: Ichneumonidae) Journal of Insect Behavior, 14 (6), 739-757 DOI: 10.1023/A:1013085316606
Stone GN, Schonrogge K, Atkinson RJ, Bellido D, & Pujade-Villar J (2002). The population biology of oak gall wasps (Hymenoptera: Cynipidae). Annual review of entomology, 47, 633-68 PMID: 11729087
