Laboratoire Ecologie and Biodiversite

Port-Saint-Louis-du-Rhône, France

Laboratoire Ecologie and Biodiversite

Port-Saint-Louis-du-Rhône, France
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Aubernon C.,University of Lille Nord de France | Aubernon C.,Forensic Taphonomy Unit | Devigne C.,University of Lille Nord de France | Devigne C.,Laboratoire Ecologie and Biodiversite | And 6 more authors.
Journal of Forensic Sciences | Year: 2015

Several parameters can delay the first arrival of flies on a corpse and the subsequent development of the larvae. This study focuses on the development of Lucilia sericata (Diptera: Calliphoridae) (Meigen, 1826) on household chemical-contaminated substrates. bleach, perfume, hydrochloric acid, caustic soda, insecticide, mosquito repellent, and gasoline in quantities consistent with an amount that could possibly be spilled on a corpse were mixed with beef liver to simulate contaminated fleshes. Larvae were bred at 25°C on these media until emergence. Four developmental parameters were followed: survival rates, development times, sex ratios, and adult sizes. Hydrochloric acid, insecticide, and gasoline killed all larvae. In low quantities, caustic soda and mosquito repellent increased the development time and decreased the adult size. However, high quantities of these chemicals killed all larvae. Lastly, bleach and perfume did not affect the survival rate and barely impacted the development time or adult size. These results demonstrate common household products spilled on a corpse can strongly affect the development of Calliphoridae larvae. The effects of such products should be considered in forensic entomology cases. © 2014 American Academy of Forensic Sciences.

Boulay J.,University of Lille Nord de France | Boulay J.,Forensic Taphonomy Unit | Boulay J.,Free University of Colombia | Devigne C.,University of Lille Nord de France | And 5 more authors.
Animal Behaviour | Year: 2013

Vectors of aggregation are well known for some arthropod species, but not for many others. We aimed to describe larval aggregation (experiment 1) in the carrion fly, Lucilia sericata (Diptera: Calliphoridae), and to investigate the effect of food and conspecifics on larval behaviour (experiment 2). In experiment 1, 40 larvae were placed in a petri dish with a homogeneous diet for 30. min, 1. h, 3. h, 5. h or 24. h. This experiment demonstrated for the first time under controlled conditions the active aggregation of L.sericata larvae. The results indicate that the aggregation took place quickly and was reinforced with time. After only 3. h, one main aggregate comprising a majority of individuals was observed. These results also highlight the likely use by necrophagous larvae of a signal left by conspecifics as an aggregation vector. In experiment 2, we used a video-tracking system to investigate whether such an aggregative signal exists. Fed and starved larvae were tracked for 5. min in a circular area with each half marked with a different signal combination. The time spent in the signal zones, the distance travelled, the velocity, the time at the stop and the number of stops in each zone were measured. The larvae were significantly retained by a signal (mark) left by conspecifics. Together, the results of this study demonstrate the existence of a contact and/or odour-mediated signal involved in the aggregative behaviour of necrophagous larvae. © 2013 The Association for the Study of Animal Behaviour.

Broly P.,Free University of Colombia | Devigne C.,Laboratoire Ecologie and Biodiversite | Devigne C.,University of Lille Nord de France | Deneubourg J.-L.,Free University of Colombia
Journal of Morphology | Year: 2015

Woodlice are fully terrestrial crustaceans and are known to be sensitive to water loss. Their half-ellipsoidal shapes represent simple models in which to investigate theoretical assumptions about organism morphology and rates of exchange with the environment. We examine the influence of surface area and mass on the desiccation rates in three eco-morphologically different species of woodlice: Oniscus asellus, Porcellio scaber, and Armadillidium vulgare. Our analysis indicates that the rate of water loss of an individual depends on both the initial weight and the body surface area. Interspecific and intraspecific analyses show that the mass-specific water loss rate of a species decreases along with the ratio of surface area to volume. In particular, we show that body shape explains the difference in mass-specific water loss rates between A. vulgare and P. scaber. This observation also explains several known ecological patterns, for example, the distribution and survivorship of individuals. However, in addition to body size and shape, water loss in terrestrial isopods depends also on the coefficient of permeability (i.e., a measure of water loss rate per surface unit), which is high in O. asellus and lower (and at similar levels) in P. scaber and A. vulgare. We discuss morphological, physiological, and behavioral aspects of water loss avoidance in terrestrial isopods. © 2015 Wiley Periodicals, Inc.

Broly P.,University of Lille Nord de France | Broly P.,Laboratoire Ecologie and Biodiversite | Broly P.,Free University of Colombia | Deneubourg J.-L.,Free University of Colombia | And 2 more authors.
Insectes Sociaux | Year: 2013

In the animal kingdom, living in group is driven by a tradeoff between the costs and the benefits of this way of life. This review focuses especially on the benefits of aggregation and crowding in woodlice (Crustacea: Isopoda: Oniscidea). Indeed, woodlice are well known to live in groups. Their aggregation behavior, as described in the early works of Allee, is regarded as a mechanism to prevent desiccation to which woodlice are extremely sensitive. However, it is now clear that there are additional benefits to aggregation in woodlice. Hence, this review addresses not only the limitation of water loss as the main factor explaining aggregation patterns, but also alternative explanations as reduction of oxygen consumption, increase in body growth, biotic stimuli for reproduction, better access to mates, possible shared defenses against predators, promotion of coprophagy as a secondary food source, sheltering behavior and the acquisition of internal symbionts. In addition, we place woodlice in the context of a terrestrialization process and propose that woodlice-the only suborder of Crustacea almost entirely composed of strictly terrestrial species-are a model taxon for studying the evolution of sociality through the transition from water to land. Further, we discuss other ultimate causes of aggregation preserved in terrestrial isopods in light of those explained in aquatic isopods and under the concept of exaptation. This knowledge could help understand, in this and other taxa, how the spatial closeness between conspecifics may promote the colonization of new environments and nonphysiological responses to climatic constraints. © 2013 International Union for the Study of Social Insects (IUSSI).

Broly P.,University of Lille Nord de France | Broly P.,Laboratoire Ecologie and Biodiversite | Broly P.,Free University of Colombia | Devigne L.,University of Lille Nord de France | And 4 more authors.
Physiological Entomology | Year: 2014

Aggregation in terrestrial isopods, a behaviour that results in the formation of dense clusters, is readily accepted as a mechanism of resistance to desiccation. Thus, aggregation is considered to be an adaptation to terrestrial life in this fully terrestrial suborder of crustaceans. In the present study of Porcellio scaber Latreille, a cosmopolitan species, individual water loss is investigated experimentally as a function of the size of the aggregates and, for the first time, over a large range of group sizes (groups of 1, 10, 20, 40, 60, 80 and 100 individuals). From the perspective of an isolated individual, aggregation behaviour is effective in reducing the rate of water loss whatever the group size, and reduces the individual water loss rate by more than half in large groups. However, the water loss rate of an individual follows a power law according to group size. Accordingly, if the addition of individuals to small groups strongly reduces the water losses per individual, adding individuals to large groups only slightly reduces the individual water losses. Thus, the successful reduction of the water loss rate by this aggregation behaviour is confirmed, although only up to a certain limit, particularly if the number of individuals per aggregate exceeds 50-60 under the experimental conditions used in the present study. Moreover, the individual surface area exposed to the air, as a function of group size, follows a similar pattern (i.e. a similar power law). Thus, a geometrical explanation is proposed for the nonlinear water losses in woodlice aggregates. These results are discussed in relation to the group sizes observed both in the laboratory and the field. © 2014 The Royal Entomological Society.

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