Editing Lytta vesicatoria (section)

== Description and ecology ==

[[File:Spanish fly in Siberia (cropped).jpg|thumb|upright=1.7|An aggregation of Spanish fly adults in Siberia. The behaviour and their toxicity suggest that their conspicuous coloration is [[Aposematism|aposematic]].<ref name="Young 1984"/>]]

The adult Spanish fly is a slender, soft-bodied metallic and [[iridescent]] golden-green insect, one of the [[blister beetle]]s. It is approximately {{convert|5|mm|in|abbr=on|1}} wide by {{convert|20|mm|in|abbr=on|1}} long.<ref name=GrzimeksAnLifeEncycl>{{cite book |editor=Schlager, Neil |year=2004 |title=Grzimek's Animal Life Encyclopedia |chapter=Coleoptera (beetles and weevils) |edition=2nd |volume=3, Insects|location=Farmington Hills, Michigan |publisher=Thomson-Gale/American Zoo and Aquarium Association |isbn=978-0787657796 |page=331 |chapter-url=http://issuu.com/radu9990/docs/grzimek-s-encyclopedia-2nd-ed.---vol.-3---insects/348 |access-date=20 December 2015 }}</ref>

The female lays her fertilised eggs on the ground, near the nest of a ground-nesting solitary bee. The [[larva]]e are very active as soon as they hatch. They climb a flowering plant and await the arrival of a [[solitary bee]]. They hook themselves on to the bee using the three claws on their legs that give the first [[instar]] larvae their name, [[triungulin]]s (from Latin ''tri'', three, and ''ungulus'', claw). The bee carries the larvae back to its nest, where they feed on bee larvae and the bees' food supplies. The larvae are thus somewhere between [[predator]]s and [[parasite]]s. The active larvae [[ecdysis|moult]] into very different, more typically [[Scarabaeoidea|scarabaeoid]] larvae for the remaining two or more instars, in a development type called [[hypermetamorphosis]]. The adults emerge from the bees' nest and fly to the woody plants on which they feed.<ref name="GrzimeksAnLifeEncycl"/><ref name="ITMA">{{cite web |title=Illustrated lecture notes on Tropical Medicine - Ectoparasites - Beetles |url=https://www.itg.be/files/docs/onderwijs/lntm2017.pdf |publisher=Institute of Tropical Medicine Antwerp |access-date=14 February 2017 |archive-date=20 January 2022 |archive-url=https://web.archive.org/web/20220120231450/https://www.itg.be/Files/docs/onderwijs/lntm2017.pdf |url-status=dead }}</ref>

The defensive chemical [[cantharidin]], for which the beetle is known, is synthesised only by males; females obtain it from males during mating, as the [[spermatophore]] contains some. This may be a [[nuptial gift]], increasing the value of mating to the female, and thus increasing the male's reproductive fitness.<ref>{{cite book |last1=Boggs |first1=Carol L. |editor1-last=Leather |editor1-first=S. R. |editor2-last=Hardie |editor2-first=J. |title=Male Nuptial Gifts: Phenotypic Consequences and Evolutionary Implications |date=1995 |publisher=[[CRC Press]] |pages=215–242 |url=https://www.researchgate.net/publication/233994025 }}</ref> Zoologists note that the conspicuous coloration, the presence of a powerful toxin, and the adults' aggregating behaviour in full view of any predators strongly suggest [[aposematism]] among the blistering meloid beetles.<ref name="Young 1984">{{cite journal |last=Young |first=Daniel K. |title=Cantharidin and insects: an historical review |journal=The Great Lakes Entomologist |volume=17 |issue=4 |year=1984 |pages=187–194 |url=https://scholar.valpo.edu/cgi/viewcontent.cgi?article=1518&context=tgle}}</ref>