Social context affects camouflage in a cryptic fish species

Crypsis, or the ability to avoid detection and/or recognition, is an important and widespread anti-predator strategy across the animal kingdom. Many animals are able to camouflage themselves by adapting their body colour to the local environment. In particular, rapid changes in body colour are often critical to the survival of cryptic prey which rely on evading detection by predators. This is especially pertinent for animals subject to spatio-temporal variability in their environment, as they must adapt to acute changes in their visual surroundings. However, which features of the local environment are most relevant is not well understood. In particular, little is known about how social context interacts with other environmental stimuli to influence crypsis. Here, we use a common cryptic prey animal, the goby ( Pseudogobius species 2) to examine how the presence and body colour of conspecifics influence the rate and extent to which gobies change colour. We find that solitary gobies change colour to match their background faster and to a greater extent than gobies in pairs. Further, we find that this relationship holds irrespective of the colour of nearby conspecifics. This study demonstrates the importance of social context in mediating colour change in cryptic animals.

Five new species of Dichaetomyia from the Malagasy Subregion (Diptera: Muscidae)

Five new species of the genus Dichaetomyia are described from Madagascar. Two species, Dichaetomyia analama sp. n. and D. necoa sp. n. belong to the subgenus Panaga. Three other species, D. amboha sp. n., D. blackia sp. n. and D. tantelya sp. n. are members of the subgenus Dichaetomyia. The body colour in normal light conditions of the five species is predominantly yellowish or grey to dark brown or blackish like most of the Afrotropical species of Dichaetomyia.

The effect of the doublesex gene in body colour masculinization of the damselfly Ischnura senegalensis

Odonata species display a remarkable diversity of colour patterns, including intrasexual polymorphisms. In the damselfly ( Ischnura senegalensis ), the expression of a sex-determining transcription factor, the doublesex ( Isdsx ) gene is reportedly associated with female colour polymorphism (CP) (gynomorph for female-specific colour and andromorph for male-mimicking colour). Here, the function of Isdsx in thoracic coloration was investigated by electroporation-mediated RNA interference (RNAi). RNAi of the Isdsx common region in males and andromorphic females reduced melanization and thus changed the colour pattern into that of gynomorphic females, while the gynomorphic colour pattern was not affected. By contrast, RNAi against the Isdsx long isoform produced no changes, suggesting that the Isdsx short isoform is important for body colour masculinization in both males and andromorphic females. When examining the expression levels of five genes with differences between sexes and female morphs, two melanin-suppressing genes, black and ebony , were expressed at higher levels in the Isdsx RNAi body area than a control area. Therefore, the Isdsx short isoform may induce thoracic colour differentiation by suppressing black and ebony , thereby generating female CP in I. senegalensis. These findings contribute to the understanding of the molecular and evolutionary mechanisms underlying female CP in Odonata.

Descriptions of five new shiny Dichaetomyia species from Madagascar (Diptera: Muscidae)

Five new species of the genus Dichaetomyia are described from Madagascar as Dichaetomyia ambrea sp. n., Dichaetomyia besseta sp. n., Dichaetomyia doubla sp. n., Dichaetomyia montea sp. n., and Dichaetomyia ranoa sp. n. The body colour of the five species is shiny metallic blue, green or violet and the colour combinations are similar to Dichaetomyia tristis (Zielke, 1972). The species, however, differ significantly from one another in other taxonomic characteristics which are commonly used in other genera to distinguish species.

Correlated evolution of parental care with dichromatism, colour, and patterns in anurans

Parental care is widespread among vertebrates, with clear fitness benefits. Caring parents however incur costs that include higher predation risk. Anurans have among the most diverse forms of parental care, and we test whether the occurrence of care is associated with morphology that minimizes predation risk. We first examine whether parental care co-occurs with sexual dichromatism, testing the hypothesis that when one sex is conspicuous, the other is cryptically patterned and cares for the young. From our phylogenetic comparative analyses of 988 anurans distributed globally, we find that parental care is less likely to co-occur with dichromatism, irrespective of the caring sex. We then examine whether colour gradients and patterns that enhance crypticity are associated with the occurrence of parental care. We found that species with male-only care were more likely to have Bars-Bands, but contrary to our expectation, other colours (Green-Brown, Red-Blue-Black, Yellow) and patterns (Plain, Spots, Mottled-Patches) were not associated with caregiving behaviours. The lack of strong correlations between dorsal morphology and parental care suggests that crypticity is not the dominant strategy to minimise predation risk for care-giving anurans, and that the evolution of body colour and parental care are driven by independent selection pressures.

Genetic parameter estimates for important traits on the fifth generation in red tilapia in Vietnam

Genetic parameters comprising heritability, genetic correlation and genotype by environment interaction (GxE) for growth survival rate and body colour at harvest were estimated on the 5th selective generation of red tilapia grown in two environments, freshwater and brackishwater ponds. A total of 116 full-half-sib families was produced as well as 4,432 and 3,811 tagged individuals were tested in freshwater and brackishwater ponds, respectively. Genetic parameters were estimated by ASReml 4.1 software. The heritability for body weight and survival rate was high while medium heritability for body colour in freshwater was observed. The heritability for those traits of red tilapia in brackishwater. Together with the figures in earlier publication on previous generations (G1 to G4) in the same selective population, the expected medium to high response acquires if selection is done for each trait. Genetic correlations among harvest body weight, survival rate and body colour are insignificantly different and ranging from -0.25 to 0.37 (P > 0.05). These results implied that selection on one trait do not influence on responses of the other traits. GxE interaction for body weight and body colour between two tested environments is mostly negligible with genetic correlations ranging from 0.63 - 0.80 while it is important for survival trait (rg = -0.17 ± 0.40).

Revision of the Empis (Enoplempis) mira species group (Diptera: Empididae)

The Empis (Enoplempis) mira species group is revised and includes the type species of Enoplempis and four new species (E. macdonaldi sp. nov., E. submira sp. nov., E. williamturneri sp. nov., E. winkleri sp. nov.). A lectotype is designated for Enoplempis mira Bigot. The species group is defined by the yellow body colour, directionally asymmetrical male hindlegs and geniculate hindlegs in both males and females. The group has not been found outside of western North America and is known from California, Oregon, Idaho and Washington.

Qualitative characteristics of Thryonomys swinderianus swinderianus and Thryonomys swinderianus gregorianus

Cane rat, a micro livestock currently being domesticated has the potential to increase animal protein sources. This study examined the qualitative characteristics of Thyryonomys swinderianus swinderianus (Tss) and Thryonomys swinderianus gregorianus (Tsg). Three hundred and thirty five cane rats were sampled. Seven qualitative characters were coded. These included: Shape of Head (SH), Eye Placement (EP), Ear Shape (ES), Body Pelage (BP), Tail Shape (TS), Tail Colour (TC), Breed (B). The qualitative characters were scored on the individual animals. This measures were analysed using frequency distribution and chi-square analysis. In the Tss population, 89.23% of the animals had broad heads, 10.77% had narrow heads. The broad heads animals had broad tip ear (89.236) have brown and yellow - belly white body colour (89.23%). Their tail is broad base and thin out to tip (87.69%) although a few (1.54%) had broad base and even out to tip. All the broad heads (89.23%) brown and yellow-belly white animals (100.00%) had black and hairy tail. In the Tsg population, 87.06% of the animals had narrow heads, (12,94%) had broad heads. The narrow heads animal (86.67%) had ear with broad tip and have black and yellow-belly white body colour (86.67%). The tail is broad base and thin out is tip (80.39%). All the narrow heads (87.06), black and yellow-belly white (99.61%) animals had black and hairy tail