Estimation of Genetic Parameters for Body Weight and Some Colour Traits in the Seventh-generation Index Selected Nigeria Heavy Local Chicken Ecotype

Background: This study was conducted to estimate the genetic parameters of body weight and some colour traits in seventh generation (G7) index selected Nigerian Heavy Local Chicken Ecotype (NHLCE) progenies at point of lay to 12 weeks. Methods: 5 sires and 12 hens were used to generate the progenies used for the experiment. Traits measured included weekly body weight, egg colour, beak colour and feather colour. Data collected were subjected to one way analysis of variance in a Paternal half sib analysis using Animal model of SAS (2003). Four weeks body weight measurements, egg colour, beak colour and feather colour for 5 sires ranged from 1.29±0.05 1.54±0.07; 2.55±0.02 to 4.00±0.02; 2.45±0.02 to 4.83±0.02 and 1.73±0.02 to 4.58±0.04 respectively. Result: The new Duncan’s multiple range test shows that sire families are similar (p greater than 0.05) in the body weight and beak colour, but significantly differed (p greater than 0.05) in the egg colour and feather colour. The heritability estimates of mature body weight for week 3 was medium, while estimates of heritability for weekly mature body weight for weeks 1, 2 and 4, egg colour, beak colour and feather colour of NHLCE were low heritability. Low h2 of traits suggest that progeny and pedigree selection could be employed for improvement of the egg colour, beak colour and feather colour of NHLCE. The study showed positive genetic correlations between beak colour and egg colour, negative genetic correlations between beak and feather colour. This means that no decision can be taken in isolation as the selection of one trait will have consequences on other traits.

Hosts elevate either within-clutch consistency or between-clutch distinctiveness of egg phenotypes in defence against brood parasites

In host–parasite arms races, hosts can evolve signatures of identity to enhance the detection of parasite mimics. In theory, signatures are most effective when within-individual variation is low (‘consistency’), and between-individual variation is high (‘distinctiveness’). However, empirical support for positive covariation in signature consistency and distinctiveness across species is mixed. Here, we attempt to resolve this puzzle by partitioning distinctiveness according to how it is achieved: (i) greater variation within each trait, contributing to elevated ‘ absolute distinctiveness’ or (ii) combining phenotypic traits in unpredictable combinations (‘ combinatorial distinctiveness’). We tested how consistency covaries with each type of distinctiveness by measuring variation in egg colour and pattern in two African bird families (Cisticolidae and Ploceidae) that experience mimetic brood parasitism. Contrary to predictions, parasitized species, but not unparasitized species, exhibited a negative relationship between consistency and combinatorial distinctiveness. Moreover, regardless of parasitism status, consistency was negatively correlated with absolute distinctiveness across species. Together, these results suggest that (i) selection from parasites acts on how traits combine rather than absolute variation in traits, (ii) consistency and distinctiveness are alternative rather than complementary elements of signatures and (iii) mechanistic constraints may explain the negative relationship between consistency and absolute distinctiveness across species.

The use of egg characters for the classification of Notodontidae (Lepidoptera), with keys to the common Palaearctic genera and species

On the basis of comparative-morphological analysis of 43 genera and 92 species of Palaearctic Notodontidae, as well as the study of the eggs of outgroup species, complexes of characters that are diagnostic, taxonomic or phylogenetic are singled out. It is shown that the egg characteristics are of great taxonomic value at species and generic levels. Some characters are useful for grouping genera. In general, a complex of characters should be used, because different species or genera often share the same characters. Possible apomorphic and plesiomorphic states of the different characters are discussed in relation to the different taxa. The results of this study are discussed with reference to recently published classifications of Notodontidae. As a result of the studies, the keys for identification to the eggs of 43 genera and 92 species of notodontid moths from the Palaearctic region are presented. Reliable diagnostic characters that do not disappear with the injury of eggs or with eggs preserved in alcohol were used. Characters including egg shape, egg and chorion colour, the shape of gnawed holes in eggs when caterpillars hatched, chorionic sculpture, the type of oviposition, foodplants, and geographic distribution of the genera and species were applied. Occasionally, characters that are typical for live eggs, which vary during development, were used. These are characters of egg colour and pattern. The keys are illustrated with photographs made using a digital camera and a scanning electron microscope.

Does coevolution with a shared parasite drive hosts to partition their defences among species?

When mimicry imposes costs on models, selection may drive the model's phenotype to evolve away from its mimic. For example, brood parasitism often drives hosts to diversify in egg appearance among females within a species, making mimetic parasitic eggs easier to detect. However, when a single parasite species exploits multiple host species, parasitism could also drive host egg evolution away from other co-occurring hosts, to escape susceptibility to their respective mimics. This hypothesis predicts that sympatric hosts of the same parasite should partition egg phenotypic space (defined by egg colour, luminance and pattern) among species to avoid one another. We show that eggs of warbler species parasitized by the cuckoo finch Anomalospiza imberbis in Zambia partition phenotypic space much more distinctly than do eggs of sympatric but unparasitized warblers. Correspondingly, cuckoo finch host-races better match their own specialist host than other local host species. In the weaver family, parasitized by the diederik cuckoo Chrysococcyx caprius , by contrast, parasitized species were more closely related and overlapped extensively in phenotypic space; correspondingly, cuckoos did not match their own host better than others. These results suggest that coevolutionary arms races between hosts and parasites may be shaped by the wider community context in which they unfold.

Egg discrimination along a gradient of natural variation in eggshell coloration

Accurate recognition of salient cues is critical for adaptive responses, but the underlying sensory and cognitive processes are often poorly understood. For example, hosts of avian brood parasites have long been assumed to reject foreign eggs from their nests based on the total degree of dissimilarity in colour to their own eggs, regardless of the foreign eggs' colours. We tested hosts' responses to gradients of natural (blue-green to brown) and artificial (green to purple) egg colours, and demonstrate that hosts base rejection decisions on both the direction and degree of colour dissimilarity along the natural, but not artificial, gradient of egg colours. Hosts rejected brown eggs and accepted blue-green eggs along the natural egg colour gradient, irrespective of the total perceived dissimilarity from their own egg's colour. By contrast, their responses did not vary along the artificial colour gradient. Our results demonstrate that egg recognition is specifically tuned to the natural gradient of avian eggshell colour and suggest a novel decision rule. These results highlight the importance of considering sensory reception and decision rules when studying perception, and illustrate that our understanding of recognition processes benefits from examining natural variation in phenotypes.

Key to the Species of Ukrainian Notodontid Moths (Lepidoptera, Notodontidae) On the Egg Characters

A key for identification of 39 species from 20 genera of Ukrainian notodontid moths based on the the eggs is provided. Reliable diagnostic characters, which do not disappear with the injury of eggs or eggs preserved for a long time in alcohol were used. The characters as egg shape, egg and chorion colour, shape of gnawed holes in eggs before setting out of caterpillars, the type of oviposition and the chorionic sculpture are applied. Clear characters that are typical for the live eggs, which vary in the process of egg development are revealed. These are characters of egg colour and pattern. In the key such characters are kept by stable signs that do not disappear aft er eggs traumatizing. The key is illustrated in details with photographs made using a digital camera and scanning electron microscope.