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Yellow Males (yellow + male)
Selected AbstractsGreater cuticular melanism is not associated with greater immunogenic response in adults of the polymorphic mountain stone weta, Hemideina maoriECOLOGICAL ENTOMOLOGY, Issue 6 2003T. Robb Abstract., 1.,Greater immune function is associated with the high-density melanic phase of polyphenic insects, appearing to compensate for density-dependent increases in susceptibility to parasites and/or pathogens. Other types of discrete variation in cuticular colour occur in insects (which may or may not be associated with melanin pigmentation), but whether this variation is predictive of immune ability has not been investigated. 2.,In the mountain stone weta Hemideina maori, a black morph and yellow banded morph occur. These morphs are not seasonally polyphenic and have discrete haplotype genetic markers. Black individuals are typically found at lower local densities than yellow individuals, contrary to relations between cuticular melanism and density seen in polyphenic insects. 3.,Yellow males and females had greater melanotic encapsulation responses upon immune challenge than did black males and females, but these differences were not associated with differences in temperature selection between morphs. Morph differences in melanotic encapsulation responses were somewhat related to differences between morphs in haemocyte concentrations. 4.,These results indicate that a common form of immune expression is not heightened with dark coloration in the mountain stone weta. Thus, earlier findings of greater immunity associated with darker cuticles in phase polyphenic insects cannot be extended to insects with other forms of discrete colour variation. These findings will help in elucidating causes and consequences of such colour polymorphism, which is widespread in several insect orders. [source] Too big for his boots: Are social costs keeping condition-dependent status signalling honest in an Australian lizard?AUSTRAL ECOLOGY, Issue 6 2009MO HEALEY Abstract Australian painted dragon lizards Ctenophorus pictus occur in three head colours (red, orange and yellow) that differ in their level of aggression (reds being most aggressive), hormone profile (reds having higher testosterone levels) and in their frequency in our study population over time. They are also polymorphic in bib colour; some males have a bright yellow area under the chin, while others lack this coloured area entirely. We show that red males with a bib are in better body condition than red males that lack a bib. This contrasts sharply to yellow males, in which males with a bib are in poorer condition than yellow males that lack a bib. Our analysis also shows that following exposure to a high percentage of red (more aggressive) neighbours, all males suffer a reduction in body condition, and importantly, males with a bib (regardless of their head colour) suffer a more severe loss of body condition than males that lack a bib. Finally, this condition loss is significantly higher for yellow bibbed males than for red bibbed males, suggesting that the cost of sporting a bib may be higher for them. Orange males showed a non-significant difference in condition between bib morphs. Our analysis also shows that bibbed yellow males (the morph with lower body condition), but no other morph category, declined significantly in their frequency between 2 years. [source] A test for negative frequency-dependent mating success as a function of male colour pattern in the bluefin killifishBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2009REBECCA C. FULLER Rare male mating advantage (a form of negative frequency dependence) is frequently proposed as a mechanism for the maintenance of genetic variation within populations. This hypothesis is attractive for systems with pronounced male colour polymorphism because it can maintain particularly high levels of variation. We tested for negative frequency-dependent mating success between yellow and red male colour patterns in bluefin killifish, Lucania goodei. Lucania goodei populations harbour substantial colour pattern polymorphism, and a large proportion of this variation has a genetic basis. We established outdoor mesocosms with red and yellow males in three different ratios: yellow rare (one yellow , : five red ,), even (three yellow , : three red ,), and red rare (five yellow , : one red ,). We obtained eggs and used microsatellites to determine paternity. By contrast to expectations, we found no support for a rare male mating advantage. Red males had slightly higher spawning success than yellow males, particularly in replicates with large clutches and when red males were rare. However, yellow males did not have higher mating success when rare. We discuss alternative mechanisms for the maintenance of the polymorphism as well as the potential reasons for the lack of a rare male mating advantage. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 489,500. [source] It is all in the head: morphological basis for differences in bite force among colour morphs of the Dalmatian wall lizardBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009KATLEEN HUYGHE Males of the lizard Podarcis melisellensis occur in three distinct colours that differ in bite performance, with orange males biting harder than white or yellow ones. Differences in bite force among colour morphs are best explained by differences in head height, suggesting underlying variation in cranial shape and/or the size of the jaw adductors. To explore this issue further, we examined variation in cranial shape, using geometric morphometric techniques. Additionally, we quantified differences in jaw adductor muscle mass. No significant differences in size corrected head shape were found, although some shape trends could be detected between the colour morphs. Orange males have relatively larger jaw adductors than yellow males. Not only the mass of the external jaw adductors, but also that of the internal jaw adductors was greater for the orange morph. Data for other cranial muscles not related to biting suggest that this is not the consequence of an overall increase in robustness in orange individuals. These results suggest that differences in bite performance among morphs are caused specifically by an increase in the mass of the jaw adductor, which may be induced by differences in circulating hormone levels. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 13,22. [source] | ||||||||||