Latrodectus woes

[Sergic]

No direct references, but several further places to look:

1) I did a search (using Yahoo!) with the search string hesperus geometricus invasive and got well over 500 hits. Also substitute mactans for hesperus. Or simply use geometricus invasive. Also use Google. I'll let you to go through all these to see if there's anything useful. (Yes, I know you've probably already done this. But remember that a lot of other people are also going to read your query and my response, and this paragraph is intended more for them.)

2) You might contact an arachnologist by the name of Rick Vetter <rick.vetter@UCR.EDU> with your question. He seems to have taken an interest in both the genera Latrodectus and Loxosceles (widows and recluses respectively).

3) Contact an animal behaviorist, Dr. Maydianne Andraden (University of Toronto, Scarborough at <mandrade@utsc.utoronto.ca>) and/or her grad student, Charmaine Condy <charmaine.condy@mail.utoronto.ca>. Charmaine is currently putting the finishing touches on her PhD thesis on the taxonomy of the genus Latrodectus.

As far as I know, none of the people who are mentioned above are actually working on the issue of the invasive nature of L. geometricus, but they all have their fingers on the pulse of the genus, so to speak, and are more likely to know where to find the information you seek.

Best of luck...

One of Dr. Andrade's other students, Monica Mowery, is studying the invasion biology of hasselti, but I don't know if her results would be generalizable to geometricus.

Cameron Jones in Andy Sih's lab at UC Davis is studying geometricus invasion. If I remember correctly, he has actually found that when you force black and brown widows to share webs, the black widows nearly always chase the brown widow off the web, and black widows are never eaten by browns. Also, I believe he has also noticed that brown widows are common in urban areas but black widows are still in the surrounding rural areas.

Clearly something is going on, but it may not be as simple as brown widows directly out competing black widows.

 

[NYAN]

Appreciate the info.

Is L. Geo proven to not tolerate cooler or wetter climates ? If so that might hopefully mean L. hesperus will survive. At least somewhere.

Supposedly geometricus comes from Africa. I’ve also seen that they stay away from drier climates. It could coincide with lack of water or lack of humans to transport them.

 

[The Snark]

When you consider the vast range of Hesperus, Canada into the Sonora desert, the Rocky mountains to the temperate rainforests of the coast, >10,000' to below sea level, Geo has it's work cut out for it displacing them all. Give it an eon or two.

Considering Hesperus range and diverse climates and environments, it was likely an opportunity invasive that found a niche in numerous ecosystems and slowly expanded.


Info on Hasseltii: https://www.magnt.net.au/magnt

 

[darkness975]

When you consider the vast range of Hesperus, Canada into the Sonora desert, the Rocky mountains to the temperate rainforests of the coast, >10,000' to below sea level, Geo has it's work cut out for it displacing them all. Give it an eon or two.

Considering Hesperus range and diverse climates and environments, it was likely an opportunity invasive that found a niche in numerous ecosystems and slowly expanded.


Info on Hasseltii: https://www.magnt.net.au/magnt

Glad there is hope for hesperus.

 

[BenLeeKing]

It's interesting that when placed together the black widows never loses against brown widows. Maybe brown widows just have a greater tolerance towards disturbances, just better at filling the gap of the displaced widows?

 

[BobBarley]

I will say that here, in Ripon, CA (an hour south of Sacramento) hesperus are thriving both in the neighborhood and in the wild. I’ve only ever seen one geometricus and it was gone within a month (unsure if it died or left). I’ve lived here for about 5 years too.