TreesTexas
Arachnopeon
- Joined
- Oct 18, 2023
- Messages
- 2
Hello! I was fortunate to come across this incredible forum and looking forward to learning from this community.
I wanted to see whether any of the experts here had any insight into a recent behavior I observed in the field in south Texas -- a Northern Black Widow (Latrodectus variolus) that had trapped and was feeding on a crab (tribe Minucini -- American Broad-front Fiddler Crabs).
I have read that Latrodectus venom contains α-latrocrustotoxin, which is toxic to crustaceans, but I haven't found anything in my (admittedly amateurish) research online indicating why or how this particular venom is useful. Does anyone know why it evolved the capacity to produce this very specific venom? Is anyone aware of similar observations documented elsewhere of predation on crabs or other crustaceans?
Some context:
- The black widow had built its web in the enclosed corner of a (now dry) concrete pool to collect rainwater for cattle. The spot with the web is about 2.5 feet deep, with sheer sides that would have made it impossible for the crab to exit once it fell in.
- This is ~2 miles from the Gulf Coast and within 100 feet of a large ephemeral pool (I think the water is brackish)
- The crab in the web was wrapped and there was a second crab in the leaf litter below (clearly wrapped and having been drained before removal from the web) so this appears to be more than a one off event.
(For more info see the iNaturalist observation here: https://www.inaturalist.org/observations/187538741)
I wanted to see whether any of the experts here had any insight into a recent behavior I observed in the field in south Texas -- a Northern Black Widow (Latrodectus variolus) that had trapped and was feeding on a crab (tribe Minucini -- American Broad-front Fiddler Crabs).
I have read that Latrodectus venom contains α-latrocrustotoxin, which is toxic to crustaceans, but I haven't found anything in my (admittedly amateurish) research online indicating why or how this particular venom is useful. Does anyone know why it evolved the capacity to produce this very specific venom? Is anyone aware of similar observations documented elsewhere of predation on crabs or other crustaceans?
Some context:
- The black widow had built its web in the enclosed corner of a (now dry) concrete pool to collect rainwater for cattle. The spot with the web is about 2.5 feet deep, with sheer sides that would have made it impossible for the crab to exit once it fell in.
- This is ~2 miles from the Gulf Coast and within 100 feet of a large ephemeral pool (I think the water is brackish)
- The crab in the web was wrapped and there was a second crab in the leaf litter below (clearly wrapped and having been drained before removal from the web) so this appears to be more than a one off event.
(For more info see the iNaturalist observation here: https://www.inaturalist.org/observations/187538741)
!!!
