Synomones in necrophagous larvae of the blow flies Lucilia sericata and Calliphora vomitoria. Issue 1 (5th October 2022)

• Record Type: Journal Article
• Authors: Fouche, Quentin; Charabidze, Damien; Lucas, Christophe
• Is Part Of: Medical and veterinary entomology. Volume 37:Issue 1(2023)
• Page Start: 170
• Page End: 175
• Publication Date: 2022-10-05
• Subjects: (Z)‐9‐tricosene -- aggregation -- Calliphoridae -- chemical communication -- decanoic acid -- dynamic headspace analysis -- mixed‐species groups -- pentadecanoic acid -- solid‐phase microextraction -- synomone; Entomology -- Periodicals; Veterinary entomology -- Periodicals; Insects as carriers of disease -- Periodicals; 616.968
• DOI: 10.1111/mve.12614
• Languages: English
• ISSNs: 0269-283X

Abstract

Abstract: Chemical signals are widespread in insects, but those resulting in interspecific communication ( i.e., synomones) remain understudied. Here, we analysed chemicals left on substrates by two species of blow fly larvae, Lucilia sericata (Meigen) and Calliphora vomitoria (Linneaus) (Diptera: Calliphoridae), which can aggregate together on carrion. Using solid‐phase microextraction and dynamic headspace analysis, we identified six compounds common to both species: the decanoic, tetradecanoic, pentadecanoic, hexadecanoic and octadecanoic acids, and the 2‐ethylhexyl salicylate. We then tested the behavioural effects of the decanoic and pentadecanoic acids using binary‐choice experiments, along with the (Z)‐9‐tricosene, a pheromone found in many arthropods. The time spent by a larva and its average crawling speed were measured in two sides of an arena, where only one contained a compound at 0.25 or 25 μg/μl. No effect was observed when testing the decanoic acid. The pentadecanoic acid only reduced the speed of C. vomitoria larvae at 25 μg/μl. Finally, L. sericata larvae spent less time in the side containing the (Z)‐9‐tricosene at 0.25 μg/μl, whereas C. vomitoria spent more time and crawled faster in this side at 25 μg/μl. Although these results did not directly evidence synomones, they suggest that the (Z)‐9‐tricosene could regulate larval aggregations on carrion. Abstract : Chemical analyses of two necrophagous flies revealed six shared compounds (mainly acids) deposited on substrate by larvae. Synomone activity was experimented using behavioural tests on both species. Shared acids only slightly influence larval behaviour, while another candidate compound ((Z)‐9‐tricosene) was either retentive for Calliphora vomitoria or repulsive for Lucilia sericata depending on concentrations. The retentive effect of the (Z)‐9‐tricosene suggests that this well‐known pheromone in arthropods (also presents in C. vicina ) could act as a synomone in blow flies, eliciting interspecific aggregation.