Environmental and evolutionary factors favouring the coexistence of sarcosaprophagous Calliphoridae species competing for animal necromass

Abstract

1. Sarcosaprophagous flies from the Calliphoridae family provide clues about the circumstances of death in criminal investigations, and apparently occupy the same ecological niche because they depend on the same ephemeral resource, namely, carrion. 2. An empirical study was conducted in southeastern New Brunswick, Canada to identify differences in Hutchinsonian hypervolume/ecological niche that allow for competitive coexistence of calliphorid species. To do this, calliphorids were trapped for a calendar year in urban, periurban, and forest habitats. 3. About 20 576 calliphorid specimens distributed among 14 different species were collected. The composition of species assemblages changed with seasons, abiotic factors, habitats, and was related to the evolutionary history of species. Each species had a distinct centroid when their response to study variables was illustrated in canonical space, thus suggesting that their ecological niches differed. 4. Examining the Hutchinsonian hypervolumes of these forensically important insects is critical because it expands our knowledge of the factors regulating the activity of calliphorid species, thereby increasing our ability to use these insects in forensic investigations.

Spatio-temporal distribution and habitat preference of necrophagous Calliphoridae based on 160 real cases from Switzerland

“…The bottle traps certainly can serve as a basic tool for monitoring of blowflies; however, the attractiveness depends on the type of bait used. Furthermore, such traps can induce biases, because they can be neglected or even avoided by certain species due to their preferred diet [3,[15][16][17] and care should be taken when extrapolating such results to case scenarios [18,19]. For example, C. vomitoria and Protophormia terraenovae are common blowflies, which can be often found on human corpses; however, they might avoid bottle traps, because they prefer a cadaver of a certain size [5,20,21].…”

Is Forensic Entomology Lost in Space?

“…Although these spatial patterns are evident, their cause cannot be determined in the present analysis and further work will be required to identify the factors involved. If we venture to speculate on this phenomenon, we can hypothesize that the synchronized spatial dynamics of these two habitat generalists in our study area [22] is due to patchy resources based on two reasons: (i) their primary resource, carrion, is ephemeral and therefore dispersed in space and time [40], and (ii) they are dominant competitors in our study area [23,41]. The less pronounced spatial aggregation of P. regina relative to L. illustris may be explained by the greater ecological plasticity of the former (e.g., its ability to feed on dung [27]) and/or by the fact that it is a late colonizer of carrion in our study area compared to L. illustris [41].…”

“…The data used in the following analyses are from a study carried out in the Greater Moncton area in New Brunswick, Canada [22]. Briefly, nine sampling sites were established on three linear transects, each containing an urban, a periurban and a forest site.…”

“…This negative spatial relationship between C. livida and all other species thus resulted in interspecific spatial segregation. As C. livida is best suited for weather conditions colder than those of late summer [22,38], the species apparently favored habitats that were not as optimal for its interspecific competitors. This demonstrates how seasonality and biotic interactions such as competition may play a role in the spatial partitioning of species [39].…”

“…Semivariograms (a,c,f,j) and crossvariograms (gray area; b,d,e,g-i) for the four most abundant Calliphoridae species during late summer 2019 in the Greater Moncton area, New Brunswick, Canada. Cali, Luil, Luse and Phre represent C. livida, L. illustris, L. sericata and P. regina, respectively.Data used to generate this figure are a subset of a previously published study[22].…”