Nouvelles
B. bohemicus male Image: Magne Flåten via wikimedia.org CC BY-SA 3.0 (B. bohemicus female here)
By Zach DeLong
When people hear of endangered species they often think of large and impressive creatures like the Siberian Tiger or Panda Bear, but we often forget about the smaller, yet no less impressive species that need our help as well. The charmingly named Cuckoo Gypsy Bumblebee, or as scientists all it Bombus bohemicus, is a member of the family Apidae, in the order Hymenoptera. Though the Species at Risk Act (SARA) currently has no status for the Cuckoo Gypsy Bumblebee, it has been recognized and listed as endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The term “endangered” is a hot topic, but there may be confusion about what it truly means. As defined by COSEWIC, an endangered species is “a wildlife species facing imminent extirpation or extinction[1]”. In the case of the Cuckoo Gypsy Bumblebee, this means the species is at risk of disappearing from the Canadian wilderness.
The Cuckoo Gypsy Bumblebee is an inquiline parasite of other types of bees, which means the Cuckoo Gypsy Bumblebee is a home invader. Normally such an invader would be attacked by the workers within the hive, but the Cuckoo Gypsy Bumblebee produces a variety of chemicals which both disguise it as a member of the host species[2] and inhibit worker aggression towards the invader[3]. The Cuckoo Gypsy Bumblebee is a generalist parasite and is surprisingly able to successfully invade a number of different Canadian species, namely the Rusty-patched Bumblebee, the Yellow-banded Bumblebee, and the Western Bumblebee[4]. Once inside the nest the Cuckoo Gypsy Bumblebee engages in a number of dominance behaviours to usurp the host queen, including ejecting host larvae from cells, eating host eggs and even outright attacking the host queen[5]. Coexistence with the host queen is preferable as her suppressor pheromones help control the workers who might otherwise attempt to become reproductively active themselves, so the invading Cuckoo Gypsy queen will often choose to shove or perform faux-stinging behaviour over outright killing her co-matriarch[5]. The Cuckoo Gypsy queen produces no workers of her own. This means she relies on host workers to defend the nest, rear her young, and forage for food[2]. Instead, all her offspring are reproductive with a 1:1 female to male ratio[6]. Young Gypsy Cuckoo Bumblebees can be seen flying about and feeding on flowers while they wait for their reproductive organs to mature so they can begin looking for a mate and a suitable host nest to invade.
Distribution of Cuckoo Gypsy Bumble Bee throughout North America. Image: COSEWIC
The Cuckoo Gypsy Bumblebee is widely distributed across a wide range in Canada, with individuals found in all provinces and territories except Nunavut[4], though populations are mostly concentrated in southern portions of Ontario and Quebec, and the Maritime provinces. Its decline across Canada has been attributed to a number of factors. It has been shown that a certain host density must be maintained for cuckoo bee parasites to be able to persist in a given area, and the general decline of bees throughout Canada has subsequently damaged Cuckoo Gypsy Bumblebee populations[4]. The mass spraying of crops with pesticides, particularly neonicotinoids, and the release of pathogen-carrying exotic bee species have impacted both cuckoo bees and host densities across Canada[4]. If we want the Cuckoo Gypsy Bumblebee to recover, perhaps the best way is to make Canada a more bee friendly environment as a whole. If we address issues resulting in the decline of other bee species, we can provide the population density necessary to facilitate persistent cuckoo populations. Additionally, addressing factors such as pesticide usage and the introduction of foreign pathogens would have positive effect on Cuckoo Gypsy Bumblebees as this would not only increase the population density of hosts, but also improve survival rates of Cuckoo Gypsy Bumblebees themselves.
References
[1]Assessment Process, Categories and Guidelines. COSEWIC. 2005-06-15. 2015-07-08. http://www.cosewic.gc.ca/eng/sct0/assessment_process_e.cfm#tbl5
[2]Kirsten Kreuter, Elfi Bunk, Anna Lückemeyer, Robert Twele, Wittko Francke, Manfred Ayasse(2012). How the social parasitic bumblebee Bombus bohemicus sneaks into power of reproduction. Behavioral Ecology and sociobiology, Vol 66, Issue 3, pp 475-486.
[3]Stephen J. Martin, Jonathan M. Carruthers, Paul H. Williams, Falko P. Drijfhout(2010). Host Specific Social Parasites (Psithyrus) Indicate Chemical Recognition System in Bumblebees. Journal of Chemical Ecology, Vol 36, Issue 8, pp 855-863.
[4]COSEWIC Wildlife Species Search: Bumble Bee, Gypsy Cuckoo | Bombus bohemicus. COSEWIC. 2002-10-21. 2011-11-07. http://www.cosewic.gc.ca/eng/sct1/searchdetail_e.cfm?id=1232&StartRow=191&boxStatus=All&boxTaxonomic=All&location=1&change=All&board=All&commonName=&scienceName=&returnFlag=0&Page=20
[5]R. M. Fisher(1988). Observations on the behaviours of three European cuckoo bumble bee species (Psithyrus). Insectes Sociaux, Volume 35, Issue 4, pp 341-354.
[6]Vergara, Carlos H. (2003). Suppression of ovarian development of Bombus terrestris workers by B. terrestris queens, Psithyrus vestalis and Psithyrus bohemicus females. Apidologie 34, pp 563–568
Fig. 1. Skillet Clubtail dragonfly adult; notice the distinctive “skillet” on tail. Photo Credit: David Marvin. Used under a Creative Commons BY-NC-ND 2.0 licence.
By Melody McLean
What if I told you that as a New Brunswicker, there are animals in danger of going extinct in your own backyard? Saying that, you’re probably thinking of a cute, fuzzy, little animal with big, sad eyes being displaced from its home. Well, that’s not what I’m referring to. I’m talking about the Skillet Clubtail Dragonfly (Gomphus ventricosus), belonging to the insect order Odonata. This dragonfly currently has no status under the Species at Risk Act (SARA), but was the only arthropod classified in the 2010 COSEWIC (Committee On the Status of Endangered Wildlife In Canada) report as being endangered. Simply put, if we don’t do something, they could become extirpated[i] from Canada or even extinct. When we hear about insects in our province, we often associate them with being pests, like spruce budworm, aphids, or disease spreading agents like mosquitos. But what we don’t often realize is that not all animals at risk of extinction are cute and fluffy. I’m here to shed some light on an underdog of the animal world, who could use a little help from us.
Insects-we can’t live with them; we can’t live without them.
What you may not know is just how thankful we (myself included) should be for insects. They clean up after us, help to provide us with rich soil for our gardens, indirectly provide us with fresh food thanks to their pollination efforts; some, like dragonflies, even keep other insects from bugging us¾like our own personal pest control.
The Skillet Clubtail dragonfly is strikingly beautiful, with green, yellow, black and brown markings running along its thorax and abdomen; transparent wings; big dark green eyes; and a distinctive circular flare, resembling a skillet, at the tip of its tail (Fig. 1).
The Biology behind the Insect
The Skillet Clubtail’s life cycle and biology is very similar to that of other dragonflies. The female lays her eggs by dipping her abdomen into the water to release them. Growing and developing, the shallowly burrowed nymphs take at least 2 years (possibly more) to develop before emerging. If conditions are right, usually in the latter 2 weeks of June, the dragonfly nymphs will find a “settle point” where the water is calm; they’ll climb up onto nearby vegetation to emerge synchronously[ii] as adults. Although the nymphs spend the majority of their lives in the water, the adults spend most of their lives around brush, fields, bogs and in the nearby canopy to forage for other insects.
Home of the Skillet Clubtail
This stunning dragonfly is restricted to North America. In Canada, it is currently found only in a few select places along the Saint John River, specifically in the Fredericton region of New Brunswick. Over 60 years ago, the Skillet Clubtail could be found in a few other locations in Canada, including Ontario, Nova Scotia and Quebec. But since there have been no recent sightings there, New Brunswick may be the last known Canadian location. The United States is running into similar problems with this insect too. It was once found in Pennsylvania and New York but is likely extirpated from both of those areas. The U.S. range extends along the Red River Basin, running from Mississippi, Tennessee, Minnesota, to the northeastern limit in New Hampshire and Maine.
Habitat: Very Important
This insect is in need of a specific and rare habitat type: a clean, large, slowly running body of water, with fine sediments and substrate, such as clay, silt, or sand, with nearby forested areas for cover. Many of these habitats are only found when the waters run through an area of rich soils, at a low gradient[iii].
99 Problems
This is where problems arise, as the Skillet Clubtail’s habitat is often prime agricultural land, where possible pollution in the river can occur, and nutrient run-off becomes a concern. Keep in mind, agriculture runoff from fertilizers, pesticides, and herbicides, are not the only culprits behind river pollution. Accidental and illegal dumping, and everyday toxins such as oil, grease, road salt, contaminants from vehicle exhaust, lawn and garden chemicals, and other harmful substances, all have a tendency to wash off lawns and roadways down to rivers and waterways. This is especially relevant here in Fredericton as the Saint John River is considered to have “marginal” water quality. As this city is literally built on a hill, all that urban runoff must go somewhere.
Although pollution is likely a major factor to this species decline, there is also the problem of sea level rise. As the sea level rises, saline water travels further up stream into the rivers, changing the chemistry of the water. This is likely to impact freshwater aquatic wildlife, as most aquatic species cannot adapt to such rapid change in their habitat. Because the farthest population is just 5 km away from the saline water limit, this is a real possibility. It’s been discussed that the Skillet Clubtail populations further upstream on the Canaan River and Salmon River could be safe from saline influence. However it has also been speculated that the main Saint John River population acts as a metapopulation, supporting the other two populations by providing immigrating individuals to them.
It’s good to note that this species needs the surrounding forest, included in its habitat. Even though mass cuttings of forests in these locations are unlikely to happen right now, we should still keep in mind deforestation has the potential to affect not only the Skillet Clubtail dragonfly, but many other species as well.
Why should you care?
Maybe you’ve gotten through this whole article and decided that you don’t care about the Skillet Clubtail Dragonfly. That’s fine. But think of it this way: the things that are likely affecting this particular dragonfly should be of broader concern to us. Chemical runoff, deforestation, general pollution and rise in sea level don’t just affect this one dragonfly species; they affect everything living that comes in contact with them, including us. The best way to finding a solution to a problem is by better understanding it through increasing our knowledge. Don’t be ignorant of the events happening in your community and environment. Take notice and do something about any detrimental events, like pollution, in your area. Dragonflies and other aquatic insects are great indicators of stream and river health, and not much is known about this particular dragonfly. So if you spot the Skillet Clubtail dragonfly, send your recordings and findings to your local Entomological Society. Many little changes have the potential to lead to one big change.
[i] Extirpated: a species that was once found in an area but is no longer found there. This is different from extinction because you can still find that particular species of animal in other areas of the country or world, therefore not totally extinct just extirpated.
[ii] They all emerge at once over a short period of time.
[iii] Low gradient streams are associated with flattened stream beds, with slow moving water and gradual, less steep slopes of surrounding valley
Figure 1 The sand-verbena moth (Photo: Wendy Gibble, Used under a CreativeCommons CC_BY 2.0 licence)
By Lisa Jørgensen
The sand-verbena moth (Copablepharon fuscum) is, when it comes to looks, a relatively anonymous fellow. This nocturnal moth, which belongs to the order Lepidoptera (butterflies and moths) and the family Noctuidae, has a wingspan of 3.5-4.0 cm and has only been found in three Canadian sites, all on the coast of southwestern British Columbia, and in a few sites in the northwestern coastal part of Washington, USA.
The moth is heavily dependent on the presence of yellow sand-verbena, as this plant is the only host that it uses for egg laying, and later for the emerging larvae and adult to feed on. The yellow sand-verbena demands sandy, nutrient poor conditions, and though it is present in areas where other plants are dominating, it will only flower at sites where it is the dominant species. The moth has been found to require large patches of yellow sand-verbena to sustain a population, but such patches are difficult to come across because of the habitat requirements of the plant.
Figure 2 Preferred habitat of yellow sand-verbena, here Long Beach Peninsula, WA, US (Photo: Wendy Gibble), Used under a CreativeCommons CC_BY 2.0 licence)
This pickiness in the moth’s choice of host plant is the most probable reason that the sand-verbena moth is considered an endangered species under the SARA (Species at Risk Act), which is the official list of Canadian wildlife at risk. The label ‘endangered’ is put on species that are in risk of extirpation or extinction, meaning that the present populations of an ‘endangered’ species are the last in the wild. We do not know how many individuals of this moth species is left, but we do know that due to plant invasion, the number of sandy patches with yellow sand-verbena is decreasing, as other plants colonize the same habitat, thus keeping down numbers of yellow sand-verbena and keeping them from flowering. When the number or size of available habitats is lowered, the moth populations will naturally experience a decrease. Another reason for the loss of habitat is the proximity of the sandy patches to the shoreline that makes the patches at risk of suffering of erosion or flooding, and the use of dunes for military training that expose the plants to the risk of being trampled down. A more direct threat to the moth than the threat of habitat loss, is the spraying of Btk (Bacillus thuringiensis kurstaki) against the larvae of pest moths, or parasitic flies introduced (i.e. not from the “hood”) for the same cause.
But why should we care about this specific endangered species? It does not play any crucial part in the pollination of yellow sand-verbena, nor is it particularly important in the local food web or to the economy, so what would happen if it we took the laissez-faire approach and did nothing to help this species? It would probably disappear from some patches, and ultimately go extinct, as it has shown poor ability into dispersal on its own. But we can do something, and it may not even cost us a lot of money (that’s a good argument, eh?)! Approaches to help recovery the Canadian populations of sand-verbena moth include the protection of patches dominated by yellow sand-verbena by physically protecting the plants from erosion and trampling by training soldiers, by fencing the area (however temporarily), and the movement of yellow sand-verbena from patches where it has a low abundance (and so no sand-verbena moth population) to patches that are in risk of being dominated by other plants (with a moth population). Also, public outreach to the areas with populations of sand-verbena moth has been initiated, and the existing populations are being monitored. The Ministry of Environment of British Columbia considers the recovery goal of the sand-verbena moth, to maintain the populations at the current locations, to be feasible.
Sources:
SARA (Government of Canada): https://www.registrelep-sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=789 25/11 2015
British Columbia Invertebrates Recovery Team. 2008. Recovery strategy for Sand-verbena Moth (Copablepharon fuscum) in British Columbia. Prepared for the B.C. Ministry of Environment, Victoria, BC. 18 pp.
The Five-spotted Bogus Yucca Moth, Prodoxus quinquepunctellus
By Isaac MacLean
Mark J. Dreiling via bugguide.net (2) CC BY-ND-NC 1.0
The Five-spotted Bogus Yucca Moth (Prodoxus quinquepunctellus) belongs to the family Prodoxidae of the Lepidoptera (moths and butterflies). It is a small, nondescript, almost entirely white moth with a few small dark spots on its forewings. Although it can be found in much of the United States, there is only one remaining population in Canada1. This species’ SARA (Species at Risk Act) status is endangered1. An endangered species is one that is very close to being extinct or extirpated. In the case of the Five-spotted Bogus Yucca Moth, it is very close to being extirpated from Canada1 (which means that the species is nearly gone in Canada, but still exists in other locations).
In order to understand where the Five-spotted Bogus Yucca Moth got its odd-sounding name, you need a little background on another moth and the plant it relies on. In Canada, Yucca is found only in Alberta1. It is a small shrub pollinated exclusively by the Yucca moth (not the “bogus” Yucca moth)1. Why do the Yucca moths pollinate Yucca plants? When a Yucca moth lays its eggs on a Yucca, they develop into larvae, and the larvae need something to feed on. The Yucca moth is the only pollinator of Yucca, and as a sort of “thank you” for pollination, some of the seeds a Yucca produces feed the developing moth larvae6.
So where do the Bogus Yucca Moths (genus Prodoxus) come into all of this? They got their “bogus” name because although they also need Yucca for their larvae to survive, they do not aid in pollination and their larvae do not feed on Yucca seeds.6 A female Bogus Yucca Moth will lay its eggs inside the flowering stalk of the Yucca plant. When the larvae emerge, they feed on the stem tissue of the Yucca1.
BIO Photography Group/CNC, Biodiversity Institute of Ontario via Boldsystems.org (3)
The Five-spotted Bogus Yucca Moth is so fragile because of its complete reliance on Yucca and Yucca Moths. If a Yucca Moth does not pollinate a Yucca’s flowers, no fruit is produced and the flowering stalk withers1. Almost all larvae within a flowering stalk that bears no fruit will be killed when it withers1. This species has been listed on SARA because in Alberta, there are only two populations of Yucca, and only one of them currently supports a population of Five-spotted Bogus Yucca Moths1. There are only an estimated 500 to several thousand Five-spotted Bogus Yucca Moths remaining in Canada1.
To keep this species from becoming extirpated from Canada, we must protect it and the species it relies on. Because of the relationship the Five-spotted Bogus Yucca Moth has with both Yucca moths and Yucca, any threat to the latter two will be an equal threat to the Five-spotted Bogus Yucca Moth. Currently, threats to Yucca and Yucca moth populations include cold weather, consumption by mule deer and pronghorn antelope, off-roading vehicles, and collection of the plant for medicinal use1,5.
Some possible actions that could be taken to minimize these threats are already being implemented through SARA and were outlined in the 2011 SARA recovery strategy for Yucca and Yucca moths. These include plans for habitat protection by limiting public access, fencing to deter mule deer and antelope, and a museum display to promote Yucca conservation6. Further action to protect the species could be implementing regulations on the collection of Yucca for medicine or horticulture. It is important to spread information about the conservation of the Five-spotted Bogus Yucca Moth, its host plant, and the Yucca moth as without public knowledge of threats to them and their habitat the risk of extirpation from Canada greatly increases.
References
- https://www.registrelep-sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=927#ot18
- http://bugguide.net/node/view/631427/bgpage
- http://www.boldsystems.org/index.php/Taxbrowser_Taxonpage?taxid=139786
- http://www.registrelep-sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=715
- Snell RS and Addicott JF. 2008. Limiting the success of stem borers (prodoxus quinquepunctellus) in yuccas: Indirect effects of ants, aphids, and fruit position. Ecol Entomol 33(1):119-26.
- http://www.registrelep-sararegistry.gc.ca/virtual_sara/files/plans/rs_soapweed_yucca_moth_0811_eng.pdf
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