O vidro repica: Fotos de April Nobile, CAS
Na súa maioría, as moscas non son un insecto que me emocione demasiado. Con todo, a enigmática familia Acroceridae son a excepción. Vou comezar a compartir algúns xéneros interesantes de cando en vez – a morfoloxía da familia é sorprendentemente diversa. Paso a maior parte dos meus días no museo inventariando a nosa enorme colección de máis 16,000 Acorcéridas (tamén coñecido como moscas de cabeza pequena). Isto pode non parecer demasiado impresionante cando o comparas con outras familias máis abundantes (e palidece en comparación co máis 17,500,000 outra exemplares que temos no museo); pero resulta que representa a moitos, se non a maioría, de todo exemplares coñecidos para toda a familia. Aínda que probablemente haxa grandes conxuntos destas moscas noutras institucións, a Academia de Ciencias de California pode facilmente reclamar o rexistro desde que recibiu a colección do Dr. Evert I. Schlinger (quen de cando en vez chega a traballar dende o museo).
Os acrocéridos resultan ser un grupo bastante difícil de estudar polo raro que son na natureza, a súa bioloxía parasitoide, e o difícil que poden ser collelos pola banda. O seu gran tórax está cheo de músculos que disparan a mosca polo aire – así que se non os colles nunha flor quedas desexando unha trampa do Malaise. Ev contoume unha historia de aprender a atrapalos na banda en Costa Rica. Estás abaixo dun compañeiro no campo – en canto alguén escoita algo pasar, balanceas salvaxe coa esperanza de atrapar a mosca por casualidade… funciona de cando en vez. Estas moscas tamén son os únicos endoparasitos coñecidos das arañas adultas (pode haber un rexistro dun taquínido…). O xénero anterior, NeoVidro, é un parasito das tarántulas Theraphosid (algo así Afonopelma). Como larva, a mosca vai subindo polas patas dunha araña e enterrase no abdome onde despois se instala xunto ao pulmón do libro e fai un pequeno orificio para respirar.. Entón espera pacientemente a que a araña chegue á madurez. Con tarántulas femininas, a mosca podería estar latente durante décadas. Finalmente sucede algo parecido á película Aliens e as larvas aliméntanse dos órganos internos da araña e emerxe para puparse.. Pero descubrir se unha araña ten ou non un parasito é imposible sen unha disección – polo que hai que manter grandes coleccións de arañas vivas para obter rexistros de hóspedes. A bioloxía parasitoide é moi xenial.
O exemplar anterior (O vidro repica unha nova, sen nome, especies) foi recollida en 1977 por Schlinger preto da cidade de Álamos, México – en flores co modelo de imitación probable, un escaravello Chrysomelidae (xente escaravello, calquera idea máis aló da familia?).
Very interesting! Out of curiosity, because you mention large collections of live spiders, has any researcher reached out to the hobby tarantula keepers in a quest for specimens? While I have never seen something as spectacular as the above emerge from a wild caught tarantula, I have heard from a few people who ended up with “strange” flies in the past…
Reaching out to them for actual tarantulas has lead to quite a few specimens for Brent Hendrixson on his revision of the genus Aphonopelma, at least for the USA native species. There also are frequently imports of various species brought in from Central and South America, which is not a practice I like or am comfortable with…but it might lead to at least a few specimens given the numbers involved. Just a thought.
I think the answer is somewhat. I’ve reached out on message boards and even recently gave a short talk to the SF Bay Area Tarantula Society. The problem comes down to peoples immediate response when they see a giant grub crawling out of their spider – they reach in and grab their prize specimen and in the process damage the larvae or pupae of the emerging fly. As it turns out these flies are pretty sensitive before pupating and while I’ve seen lots of maggot images, never seen a fly reared by a hobbyist. I think the biggest hurdle is that people only discover what they are after they have had a spider die – and chances are it’ll be years before another one of their wild caught immature spiders are parasitized!
That makes a lot of sense, I guess it didnt really occur to me that for most people having a parasite emerge from one of their captives is a bad thing…that sort of thing would make my day. 🙂
Especially if that spider cost you a few hundred dollars!!
I wonder if that fly sees very well. 🙂
First impression of the beetle is a species of Chrysolina (subfamily Chrysomelinae), but my knowledge of Neotropical chrysos is limited.
Thanks for the genus ballpark – I’ll have to dig through our collections here to see if I can’t narrow it down more.
Did you mean that these acrocerid flies are the only known dipteran endoparasites of adult spiders? There are certainly spider-parasitic nematodes, and mantidfly larvae can crawl into the book lungs of their spider hosts and feed on hemolymph while hitching a ride to the egg deposition site.
http://en.wikipedia.org/wiki/Mantispidae
And here’s a cool post about a mantidfly larva on a spider, preserved in amber!
http://blogs.discovermagazine.com/notrocketscience/2011/03/28/spider-boarding-insect-preserved-in-amber/
(Claro, that one’s on the outside of the spider, but the post also has more info on other tactics.)
Thank you for pointing that out! You’re correct of course, when I was thinking “no other endoparasitoids” I totally neglected non-insects such as nematodes. I should have recalled how tricky it can be to control nematode infestations in captive bread spiders!
I also did not know that about mantidflies. Actually I should catch up on the literature, there may be other diptera or hymenoptera parasitoids more recently known. Very cool, thanks for the link.
Augh augh augh and here’s a picture of a huuuuuge nematode coming out of a spider! It’s even one of the behavior-modifying parasites — it induces its host to seek out water before dying, so the nematode can complete its life cycle. (Like the horsehair worm in crickets!)
http://www.abc.net.au/science/k2/stn/spider.htm