Sepsis duplicata showing the setae on mid and hind femurs - Copyright Diptera Identification Service 2025

PDF | On Jan 1, 2002, Adrian C. Pont and others published The Sepsidae (Diptera) of Europe | Find, read and cite all the research you need on ResearchGate

Publication date: Available online 7 January 2026 Source: Behavioural Processes Author(s): Amir Tarizadeh, Marjan Seiedy

PDF | On Jan 1, 2002, Adrian C. Pont and others published The Sepsidae (Diptera) of Europe | Find, read and cite all the research you need on ResearchGate

Abstract The influence of pre-copulatory courtship on mate acquisition has been well explored but the effects of copulatory courtship (or behaviours occurring after intromission) on reproductive fitness largely remains underexplored. In insects, behaviour performed during copulation often involves rapid, successive movements with several limbs and wing beats, which are often difficult to observe and quantify. There is also a lack of understanding of how behavioural plasticity can compensate for physical impairments (e.g. loss of limbs) during copulation. Here, we studied the reproductive consequences of limb loss using two North American (NA) and two European (EU) populations of Sepsis punctum flies that are known to employ various limbs to interact with females during copulation. We observed plasticity in copulatory behaviour as a consequence of limb loss, giving rise to novel behavioural characters. The loss of different sets of limbs (forelegs vs. midlegs vs. hindlegs) significantly decreased mating success (i.e., successful copulations), but individuals that did copulate, did not vary in fertilisation success (i.e., number of offspring), suggesting that plasticity in copulatory behaviour has consequences for mate acquisition and less for fertilization success. Notably, we observed population level differences in baseline copulatory behaviour, and higher levels of plasticity for EU populations when compensating for limb loss impairments. Our results suggest that limb loss in S. punctum males influences the behavioural repertoire performed during copulation, but population-specific differences in plasticity may be able to compensate for reproductive success. Significance statement Courtship influences non-random mate choice via mate acquisition and fertilisation success. Across the courtship phases (pre-copulatory, copulatory, and post-copulatory), copulatory behaviours remain a mystery. The widespread dung fly, Sepsis punctum, displays a variety of contact behaviours using all sets of limbs. We observed continental differences between North American and European populations, with North American populations displaying a wider repertoire of copulatory behaviours. We also observed that the loss of different sets of limbs (e.g. forelegs, midlegs, hindlegs) impacted mate acquisition to different extents but it did not significantly influence fertilization success. Notably, novel copulatory behaviours and behavioural plasticity could rescue copulatory courtship particularly with the loss of midlegs that are important for behavioural interactions in sepsid flies.

Abstract The influence of pre-copulatory courtship on mate acquisition has been well explored but the effects of copulatory courtship (or behaviours occurring after intromission) on reproductive fitne...

Family Sepsidae. Also known as black scavenger flies, and at Brisbane Insects as Ant Flies. From Wikipedia: There are approximately 250 species worldwide. They are usually found around dung or...

Photos 1-2 - Sepsidae: Parapalaeosepsis sp. Photos 3-4 - Muscidae: Graphomya sp. Photos 5-6 - Acalyptratae sp. Photos 7-8 - Tachinidae sp. (multiple specimens) Photos 9-10 - Muscidae: Limnophora sp....

Publication date: Available online 7 January 2026 Source: Behavioural Processes Author(s): Amir Tarizadeh, Marjan Seiedy

AbstractMyrmecomorphy is the most prevalent type of Batesian mimicry among arthropods. Some species of the fly family Sepsidae also bear resemblance to ants. We examined whether the black scavenger fly, Sepsis thoracica, bears a phenotypic resemblance to the abundant ant Lasius niger (workers and males), and whether this resemblance protects it from predation by the syntopic wolf spider Pardosa agrestis. We compared the motion, body shape, size, and coloration traits of S. thoracica to Lasius workers and males, as well as to Drosophila hydei, a non-mimetic fly. Overall, S. thoracica resembled Lasius ant males in motion and body shape, D. hydei in size, and Lasius workers in coloration. Visual models of spider and avian predators revealed that in terms of luminance, S. thoracica was indistinguishable from ant males but different from D. hydei. In predation experiments, S. thoracica was preyed upon less frequently by spiders than D. hydei, and at a frequency similar to ant males. The low consumption frequency of S. thoracica was presumably in part due to the release of defensive chemicals. We conclude that it is an inaccurate Batesian mimic of several Lasius species. This paper brings the first empirical evidence of myrmecomorphy in flies.

Abstract The influence of pre-copulatory courtship on mate acquisition has been well explored but the effects of copulatory courtship (or behaviours occurring after intromission) on reproductive fitness largely remains underexplored. In insects, behaviour performed during copulation often involves rapid, successive movements with several limbs and wing beats, which are often difficult to observe and quantify. There is also a lack of understanding of how behavioural plasticity can compensate for physical impairments (e.g. loss of limbs) during copulation. Here, we studied the reproductive consequences of limb loss using two North American (NA) and two European (EU) populations of Sepsis punctum flies that are known to employ various limbs to interact with females during copulation. We observed plasticity in copulatory behaviour as a consequence of limb loss, giving rise to novel behavioural characters. The loss of different sets of limbs (forelegs vs. midlegs vs. hindlegs) significantly decreased mating success (i.e., successful copulations), but individuals that did copulate, did not vary in fertilisation success (i.e., number of offspring), suggesting that plasticity in copulatory behaviour has consequences for mate acquisition and less for fertilization success. Notably, we observed population level differences in baseline copulatory behaviour, and higher levels of plasticity for EU populations when compensating for limb loss impairments. Our results suggest that limb loss in S. punctum males influences the behavioural repertoire performed during copulation, but population-specific differences in plasticity may be able to compensate for reproductive success. Significance statement Courtship influences non-random mate choice via mate acquisition and fertilisation success. Across the courtship phases (pre-copulatory, copulatory, and post-copulatory), copulatory behaviours remain a mystery. The widespread dung fly, Sepsis punctum, displays a variety of contact behaviours using all sets of limbs. We observed continental differences between North American and European populations, with North American populations displaying a wider repertoire of copulatory behaviours. We also observed that the loss of different sets of limbs (e.g. forelegs, midlegs, hindlegs) impacted mate acquisition to different extents but it did not significantly influence fertilization success. Notably, novel copulatory behaviours and behavioural plasticity could rescue copulatory courtship particularly with the loss of midlegs that are important for behavioural interactions in sepsid flies.