			Home About us Contact

Chewing Lice (chewing + louse)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Uropygial gland size correlates with feather holes, body condition and wingbar size in the house sparrow Passer domesticus

JOURNAL OF AVIAN BIOLOGY, Issue 3 2010
Gregorio Moreno-Rueda
The uropygial gland is an organ exclusive of birds that secretes an oily substance, the uropygial secretion, the functions of which are still debated. One of the proposed hypothesis is its possible action against chewing lice (order Phthiraptera), a group of avian ectoparasites that feed on feathers, causing different types of harm. However, this hypothesis lacks support. The present study analyses the relationship between uropygial gland size and the number of feather holes (which is correlated with the load of chewing lice) in the house sparrow Passer domesticus. Moreover, the relationship between the uropygial gland size and different aspects of sparrow health (body condition, immunocompetence and haematocrit), as well as sexually selected traits in males (badge and wingbar size), is tested. The results show a negative correlation between uropygial gland size and number of feather holes, a result found both years of the study. This result supports the hypothesis that uropygial secretion is used against chewing lice. Uropygial gland size also correlated positively with body condition (residuals of body mass relative to tarsus length) and immunocompetence, being therefore related to bird health. After a year in captivity, with resources provided ad libitum, no correlation was found between individual uropygial gland size and body condition or haematocrit, perhaps because the negative effect that chewing lice exert on bird health was offset by captivity conditions. Uropygial gland size was not correlated with badge size, but it was correlated with wingbar size, which furthermore supports the contention that this sexually selected signal acts as an indicator of lice resistance in the house sparrow. In summary, this study supports the idea of a positive relationship between uropygial gland and bird health in the house sparrow, the gland secretion affording resistance against chewing lice. [source]

Comparative body size relationships in pocket gophers and their chewing lice

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2000
SERGE MORAND
In this paper, we use the method of independent contrasts to study body size relationships between pocket gophers and their chewing lice, a host-parasite system in which both host and parasite phylogcnies are well studied. The evolution of body size of chewing lice appears to be dependent only on the body size of their hosts, which confirms the 1991 findings of Harvey and Keymer. We show that there is a positive relationship between body size and hair-shaft diameter in pocket gophers, and that there is also a positive relationship between body size and head-groove width in chewing lice. Finally, we show a positive relationship between gopher hair-shaft diameter and louse head-groove width. We postulate that changes in body size of chewing lice are driven by a mechanical relationship between the parasite's head-groove dimension and the diameter of the hairs of its host. Louse species living"on larger host species may be larger simply because their hosts have thicker hairs, which requires that the lice have a wider head groove. Our study of gopher hair-shaft diameter and louse head-groove dimensions suggest that there is a ,lock-and-key' relationship between these two anatomical features. [source]

Host,parasite interactions and vectors in the barn swallow in relation to climate change

GLOBAL CHANGE BIOLOGY, Issue 4 2010
A. P. MØLLER
Abstract Recent climate change has affected the phenology of numerous species, and such differential changes may affect host,parasite interactions. Using information on vectors (louseflies, mosquitoes, blackflies) and parasites (tropical fowl mite Ornithonyssus bursa, the lousefly Ornithomyia avicularia, a chewing louse Brueelia sp., two species of feather mites Trouessartia crucifera and Trouessartia appendiculata, and two species of blood parasites Leucozytozoon whitworthi and Haemoproteus prognei) of the barn swallow Hirundo rustica collected during 1971,2008, I analyzed temporal changes in emergence and abundance, relationships with climatic conditions, and changes in the fitness impact of parasites on their hosts. Temperature and rainfall during the summer breeding season of the host increased during the study. The intensity of infestation by mites decreased, but increased for the lousefly during 1982,2008. The prevalence of two species of blood parasites increased during 1988,2008. The timing of first mass emergence of mosquitoes and blackflies advanced. These temporal changes in phenology and abundance of parasites and vectors could be linked to changes in temperature, but less so to changes in precipitation. Parasites had fitness consequences for hosts because intensity of the mite and the chewing louse was significantly associated with delayed breeding of the host, while a greater abundance of feather mites was associated with earlier breeding. Reproductive success of the host decreased with increasing abundance of the chewing louse. The temporal decrease in mite abundance was associated with advanced breeding of the host, while the increase in abundance of the lousefly was associated with earlier breeding. Virulence by the tropical fowl mite decreased with increasing temperature, independent of confounding factors. These findings suggest that climate change affects parasite species differently, hence altering the composition of the parasite community, and that climate change causes changes in the virulence of parasites. Because the changing phenology of different species of parasites had both positive and negative effects on their hosts, and because the abundance of some parasites increased, while that of other decreased, there was no consistent temporal change in host fitness during 1971,2008. [source]