Handling live redback spiders: keep cool?

Mortal peril, danger, excitement, injuries, scientist. Not all of these words usually go together. People would rarely equate being a zoologist as a high risk professions. These same people are quite happy to accept the Steve Irwins and Bear Grylls of this world and appreciate the danger that they are in as they mess about with the wildlife but seldom spare a thought for the zoologists that actually study the crocodiles that Steve used to wrestle or the snakes that Bear gnaws on. Scientists are usually safe in their labs or slaving over a hot computer. Aren’t they? Well, yes, most of us spend a lot of time in offices and labs. Labs, actually, are dangerous places. One of the most high risk thing that I have done was mixing incredibly toxic and potent chemicals way back in the 1990s when I was doing allozyme analyses in a lab. Still, I guess that’s not the same as facing down a tiger. Sometimes the locations that we find ourselves doing research in is the risky part. As part of my PhD I needed to collect seabird samples. Often these birds lived on small rocks off the coast, only accessible by leaping from a rocking boat onto slippery and seaweed strewn rocks, (and then having to do the reverse – even more difficult). Or carefully climbing along cliffs at the end of the world (well Codfish Island), hours from help because that’s where the prions lived.

Adrian and noose mat

Adrian handling a Chatham Island Oystercatcher – watch out for the beak, you could lose an eye!

Of course, it’s the animals that really count though. One of the perks of being a zoologist is getting up close to animals. We usually need to handle animals so that we can move them for observation, manipulate them for experiments or to get samples (like blood or parasites) off them. I remember that the highlight of my undergraduate degree was doing a physiology lab on young tuatara. What a buzz to work and handle these small pieces of evolution royalty! Until we misplaced one and spent the worst 15 minutes of my undergrad finding the little so and so (hey they move fast when you aren’t watching them!). I have handled plenty of seabirds (from tiny storm petrels to 10kg albatrosses) but they are pretty cute and harmless (except for regurgitating stomach oils on you). The Westland Black Petrel has an extraordinary bite and we had to use welding gloves to handle those but no-one is likely to lose a limb. Similarly, kea have powerful pointy beaks and know how to use them. Penguins are mostly good to handle (apart from Blue penguins who suffer from short penguin syndrome). Shags (watch out for the lunging snake-like neck and head), black-backed gulls (we were in more danger from the bacteria at the tip where we collected) and oystercatchers (too cute and cool to do much of anything) were somewhat unimpressive from the terror point of view. Lizards? Yawn. Mammals? Well fur seals were more of a challenge. We had to catch young seals and they can bite (indeed one of my colleagues nearly died from an infected bite at one point).  Invertebrates? Most have been extremely harmless. Hepialid moths, preying mantids, Dolomedes spiders and knobbled weevils might look icky and dangerous, but they aren’t. Honey bees can sting but if you work with them calmly you should be alright (and I was over a two year period). Which leaves a couple of dangerous animals that I have had to work with.

red back on web

An Aussie redback – now these really are dangerous to handle.

Katipo and redback spiders are members of the widow family. Widow spiders generally have very nasty toxins that can make you sick (katipo) or even kill you (redbacks). I have had several students (and a son doing a science project) work on katipo over the years. We often spend a lot of time looking for this threatened native species in some of the dune regions around Christchurch, turning over driftwood or inspecting sand-binding grasses. Sometimes we have brought them back to the lab to live while we work with them. Redbacks are an Australian species that have successfully established themselves in a few parts of New Zealand. We have had spiders in our labs so that we can look at whether they interbreed with native katipo (they do) and what they eat and so on. Often it is useful to handle the individuals and obviously we would rather handle an immobilised individual than one that can scamper about with its lethal bite. Vikki Smith (Lincoln University PhD student) with her supervisors Cor Vink (Canterbury Museum and all round spiderman) and Adrian Paterson (Lincoln University ecologist) were looking at katipo habitat preferences and needed a way in which they could measure widow spiders accurately, and non-lethally as we want to keep the katipo alive. Vikki’s findings have been published in New Zealand Entomologist.

red back being measured2

Stay still! Measuring a spider is challenging.

Vikki looked at two methods for immobilising widow spiders long enough to take some measurements. Exposing arthropod species to small blasts of CO2 has worked previously, including for spiders. The CO2 interferes with connections between nerves and muscles immobilising the individual. Another method is to cool down the spider and induce a chill-coma which seem to shut down cell membrane functions. Vikki used 8 individual redbacks obtained from Central Otago, put them through different sets of trials and looked at how active they were after being gassed or cooled. Vikki found that cooling the spiders was not particularly useful. Using gas was more effective but only if the spider was placed in CO2 gas for about a minute or more. This would allow enough immobilisation time for measurements to be made before activity returned. So when faced with a redback spider keeping cool was not as good as getting gassy! Another example of zoologists making the world a safer place from dangerous critters. Or at least making it safer for us to work with dangerous critters.

One thought on “Handling live redback spiders: keep cool?”

  1. John Dayton says:

    I worked for a time with a device designed for keeping fruitflies immobilized for sorting under a dissecting microscope. The device consisted of a small box with a ceramic, gas permeable, top surface that was flat and white (a ceramic filter plate?). The box was otherwise sealed except for a small tubing cock and contained an air space (~0.5 cm high). It fit nicely on the microscope stage and was stabilized with rubber feet. A tube was then connected from the box to the CO2 tank or dry ice chamber. The fruitflies were initially gassed in a vial until they stopped moving (a very short time as I recall); they were then dumped onto the sorting table. The CO2 flow to the table was controlled with a pinchcock so that the gas slowly diffused through the ceramic plate keeping the fruitflies just enough under to tolerate the sorting. Seems like a similar device could be used for your much more hazardous spiders.

    Sorry if you have already discussed this idea in your paper; but my access was limited to the abstract.

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