Communication in necrophagous Diptera larvae: interspecific effect of cues left behind by maggots and implications in their aggregation

Quentin Fouche,Damien Charabidze,Valery Hedouin

doi:10.1038/s41598-018-21316-x

Quentin Fouche, Damien Charabidze + Show 1 more

Open Access

https://doi.org/10.1038/s41598-018-21316-x

Copy DOI

Abstract

Necrophagous Calliphoridae breed in vertebrate carrion. Their larvae aggregate and form large masses of individuals. These aggregated larvae can reach adulthood faster than scattered larvae, increasing their chances of survival. Furthermore, the gathering of larvae of different species suggests possible interspecific aggregation vectors. In this context, the effect of larval ground-left cues on larvae of Calliphora vomitoria and Lucilia sericata was studied. We used video tracking to follow larvae placed in binary choice tests. We observed (1) a preference of both species for a side marked by conspecific or heterospecific larvae compared to an unmarked side, (2) a preference of L. sericata larvae for a conspecific-marked side compared to a heterospecific-marked side but only at high concentration of cues and (3) a preference of both species for the side marked by the greater number of larvae. These results demonstrate that larvae leave a mark locally which is retentive, has an interspecific range, has an effect proportional to its intensity and whose strength varies depending on the emitting species. According to the self-organization theory, this mark could enhance larval gathering and promote interspecific aggregations. While not yet demonstrated, an interspecific Allee effect could explain the interspecific association of necrophagous calliphorid larvae.

Highlights

IntroductionA striking consequence of larval aggregation, the so-called maggot-mass effect, is a local temperature increase which can reach 20 °C above ambient
The present study investigates the interspecific effect of the cuticular ground-left cues of C. vomitoria and L. sericata larvae
The same result was observed for the heterospecific cue: when one side of the arena was previously marked by five heterospecific larvae, both L. sericata and C. vomitoria larvae spent significantly more time and travelled greater distances in the heterospecific-marked side (Table 1, Fig. 3)

Summary

Introduction

A striking consequence of larval aggregation, the so-called maggot-mass effect, is a local temperature increase which can reach 20 °C above ambient This heat production is proportional to the number of larvae in the aggregate[18,19]. As the developmental speed of larvae increases with temperature[20], aggregated larvae benefiting from the larval-mass effect can reach adulthood faster than isolated individuals[21,22,23,24] This reduced development time likely increases the chances of survival of larvae, while aggregation confers other benefits such as better nutrients absorption and protection against www.nature.com/scientificreports/. A recent study demonstrated larval social aggregation in two blowfly species, the common green bottle fly Lucilia sericata and the blue bottle fly Calliphora vomitoria[12] This result suggests possible aggregation vectors shared between the two species[12]. This could promote aggregation of larvae and constitute an aggregation vector[26]

Methods

Results

Conclusion