title: To eat or get heat: Behavioral trade-offs between thermoregulation and feeding in gregarious necrophagous larvae.
abstract: The thermoregulation behavior of Lucilia sericata larvae (Diptera: Calliphoridae), a necrophagous species that feeds on vertebrate cadavers, was investigated. These larvae require high heat incomes to develop, and can elevate temperatures by forming large aggregates. We hypothesized that L. sericata larvae should continue to feed at temperatures up to 38 °C, which can be reached inside larval masses. Thermal regulation behavior such as movement between a hot food spot and colder areas was also postulated. The hypotheses were tested by tracking for 1 h the activity of single, starved third instar larvae in a Petri dish containing 1 food spot (FS) that was heated to a constant temperature of 25 °C, 34 °C or 38 °C with an ambient temperature of 25 °C. The influence of previous conspecific activity in the food on larval behavior was also tested. The crops of larvae were dissected to monitor food content in the digestive systems. Based on relative crop measurements, larvae fed at all food temperatures, but temperature strongly affected larval behavior and kinematics. The total time spent by larvae in FS and the duration of each stay decreased at high FS temperature. Previous activity of conspecifics in the food slightly increased the time spent by larvae in FS and also decreased the average distance to FS. Therefore, necrophagous L. sericata larvae likely thermoregulate during normal feeding activities by adjusting to local fluctuations in temperature, particularly inside maggot masses. By maintaining a steady internal body temperature, larvae likely reduce their development time.
authors.affiliation: Department of Zoology, Fisheries, Hydrobiology and Apiculture, Mendel University in Brno, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Podhorna
authors.affiliation: Unité de Taphonomie Médico-Légale, University of Lille, CHU Lille, EA, France.
authors.forename: Cindy
authors.initials: C
authors.lastname: Aubernon
authors.affiliation: Department of Zoology, Fisheries, Hydrobiology and Apiculture, Mendel University in Brno, Czech Republic.
authors.forename: Marie
authors.initials: M
authors.lastname: Borkovcova
authors.affiliation: Unité de Taphonomie Médico-Légale, University of Lille, CHU Lille, EA, France.
authors.forename: Julien
authors.identifier: http://orcid.org/0000-0002-1403-8822
authors.initials: J
authors.lastname: Boulay
authors.affiliation: Unité de Taphonomie Médico-Légale, University of Lille, CHU Lille, EA, France.
authors.forename: Valery
authors.initials: V
authors.lastname: Hedouin
authors.affiliation: Unité de Taphonomie Médico-Légale, University of Lille, CHU Lille, EA, France.
authors.forename: Damien
authors.identifier: http://orcid.org/0000-0002-9935-1956
authors.initials: D
authors.lastname: Charabidze
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation; D004175:Diptera / Q000254:growth & development / Q000502:physiology*; D005247:Feeding Behavior; D006358:Hot Temperature; D007814:Larva / Q000254:growth & development / Q000502:physiology
keywords: Calliphoridae; blowflies; foraging; forensic entomology; thermoregulation; video tracking