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Behavioural observations in nature reveal mating strategies of jumping spiders

—- By Gwylim S. Blackburn & Wayne P. Maddison—-

Animals reveal a lot about their lives simply by the way that they behave. When observed in the wild, they also offer insights to the function of behaviours in a natural context. Capturing these insights just requires a little patience, and attention to the right details.

In a recent study printed in the journal Behaviour, we set out to document Habronattus americanus jumping spider behaviors that would shed light on their ‘mating strategies’—the tactics used by females and males to acquire mates. Specifically, we wanted to know if males show off their flashy displays only to females or also compete directly with each other, if they invest heavily in mate search, and if females are choosy when deciding who to mate with.

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An adult male Habronattus americanus jumping spider travels through beach habitat in British Columbia, Canada. The bright coloration on his face and legs is presented to females during elaborate courtship dances. Photo credit: Sean McCann.

To pursue these issues, we followed 41 adults for up to 30 minutes each, and we also staged interactions between an additional 36 male-female pairs, in natural habitat.

Typical Habronattus americanus habitat is fairly flat, well-drained, and sparsely covered with plants, sticks, or pebbles. Photo credit: Maxence Salomon

Typical Habronattus americanus habitat is fairly flat, well-drained, and sparsely covered with plants, sticks, or pebbles. Photo credit: Maxence Salomon

The behaviours of both sexes pointed quite strongly to indirect male competition for choosy females. Males did not display to (or fight with) each other. Instead, they travelled far and wide, eating nothing but displaying to every female they met. Females, on the other hand, focused on hunting rather than travel, and they almost never permitted copulation despite the vigorous courtship efforts of males.

Collectively, these behaviours supply deeper lessons than their individual functions; they also indicate how natural selection might shape several of the traits involved. In particular, our findings suggest that female mate choice may be the key source of selection favouring the evolution of male display traits.

An adult female Habronattus americanus jumping spider in natural beach habitat. Females are avid hunters. Photo credit: Sean McCann

An adult female Habronattus americanus jumping spider in natural beach habitat. Females are avid hunters. Photo credit: Sean McCann

The apparently high investment by males in mate search also represents a potential factor shaping female mate preferences. In a variety of other species, mate search costs have been shown to provide a way for females to judge the quality of prospective mates. This is because males who are able to pay those costs while still producing an impressive display can make better fathers (e.g., by providing better parental care, or by passing along advantageous genes to their offspring). To determine if this is the case in H. americanus, further research will be needed to see how male condition is linked to the quality of their displays and the success of their offspring.

The Habronattus jumping spiders are famous for their stunning array of male displays. It would be fascinating to know how mating strategies, and the natural surroundings in which they unfold, have influenced this diversity. Behavioural observations of different species in the wild will be essential for getting at this question.

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Exotic field collecting…in the hallway!

The following post is by Chloe Gerak, a Masters student at UBC who completed an undergraduate project at Simon Fraser University in the Gries lab.This past weekend, she won the top prize for an undergraduate talk at the Annual General  Meeting of the Entomological Society of British Columbia with a talk entitled “How the false widow finds true love”. Photos by Sean McCann.

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A male Steatoda grossa. These spiders have stereotyped courtship behaviour involving stridulation of an organ located dorsally between the cephalothorax and abdomen.

For approximately eight months, I studied the courtship behaviour and chemical communication between male and female false widow spiders, Steatoda grossa. Prior to studying them in Prof. Gerhard Gries’ lab at Simon Fraser University, I had never even heard of this species!

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Female Steatoda grossa on her web.

My mentor Catherine Scott and I had collected juvenile and mature false widow spiders around the basement of the biology wing at SFU… and let’s just say we didn’t have a lack of specimens to collect. Almost every baseboard we turned over or corner we searched, we would find these little guys and collect them individually into petri dishes. These formed the nucleus of our laboratory colony which we reared for behavioural experiments.

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A  common nickname for Steatoda grossa is the “cupboard spider,” which I find extremely appropriate considering these spiders seem to love dwelling in dark corners. Since they are so abundant around SFU, and I had never even seen one before this, I think people should not be frightened by cohabiting with them… likely, you won’t even know they are there!

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How to get a spider to drink blood

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Spiders may not bite, but that doesn’t mean you can’t get them to drink your blood! All you need is a sunset at the beach, hordes of mosquitoes, a spider, and some frustration to take out.

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The other night, I was unwinding with an evening of wasp and bee photography at Iona beach, but the flight conditions were great for mosquitoes. They kept interrupting my shots of this lovely Tetragnatha laboriosa, so I decided to share the wealth.

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Trapping the mosquito against my skin, I released it in the sweet spot of the web.

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You can see the movement of the wrapping action, as I was also dragging the shutter to get some light in the darkening sky.

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I was looking forward to a great splash of blood as the spider bit in!

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This is about as good as it got however, but I am sure the spider will appreciate the extra protein already in liquid form.

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This one is pretty cool too…

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The mozzies kept biting, so I kept tossing them into the web.

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I kept the spider busy wrapping up her gifts for quite a while.

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When we both had had enough, I headed home, feeling itchy, but satisfied that I had at least achieved the fattening up of a cool tetragnathid.

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Friday night fun: spiders at Iona Beach

 

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Samantha Vibert, Gwylim Blackburn, Catherine Scott and Sam Evans in the midst of examining an unidentified jumping spider.

Yesterday, I had the pleasure of ferrying four Vancouver-area spider researchers out to Iona Beach in Richmond for a bit of a Friday-evening ramble in search of spiders. Gwylim Blackburn and Samantha Vibert are old hands at spider observations at this site, Gwilym had studied Habronattus americanus and Samantha  had studied Hobo Spiders. Catherine Scott (who studies black widows) and Sam Evans (a recent recruit to Wayne Maddison’s lab) came along as well.  This was a Toyota Tercel loaded down with spider talent!

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Daisy did not ask for this in her old age, but performed admirably nonetheless.

 

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We arrived shortly after 7 pm, and despite the late hour, we found a few jumping spiders, although Habronattus americanus was already in bed. I only managed to sneak in a couple photos of large Phidippus.

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Sam searches among moss and Scotch Broom.

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A long-jawed orbweaver male (Tetragnathidae) tucked in with a pupating beetle.

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A freshly-moulted harvestperson with exuvium still attached!

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A large ichneumonid among pine needles.

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A 10-lined june beetle larva under a log.

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A wolf spider in her burrow with a freshly-laid eggsac.

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Gwylim searches the beach.

Just before the gates were due to close at the park, we spotted a couple of snails, seemingly uncaring of our log-flipping sharing a tender moment. We hope they had a fun night!