STRESS AND IMMUNE RESPONSES OF NESTLING TREE SWALLOWS (TACHYCINETA BICOLOR) AND EASTERN BLUEBIRDS (SIALIA SIALIS) EXPOSED TO NONPERSISTENT PESTICIDES AND p,p′-DICHLORODIPHENYLDICHLOROETHYLENE IN APPLE ORCHARDS OF SOUTHERN ONTARIO, CANADA

2004 ◽  
Vol 23 (12) ◽  
pp. 2930 ◽  
Author(s):  
Gregory J. Mayne ◽  
Pamela A. Martin ◽  
Christine A. Bishop ◽  
Herman J. Boermans
Ecotoxicology ◽  
2005 ◽  
Vol 14 (3) ◽  
pp. 381-396 ◽  
Author(s):  
Gregory J. Mayne ◽  
Christine A. Bishop ◽  
Pamela A. Martin ◽  
Herman J. Boermans ◽  
Bruce Hunter

2013 ◽  
Vol 91 (2) ◽  
pp. 56-63 ◽  
Author(s):  
G. Pigeon ◽  
R. Baeta ◽  
M. Bélisle ◽  
D. Garant ◽  
F. Pelletier

Lower immune response usually translates into lower fitness. Environmental quality can play a key role in shaping immune responses in the wild, as it influences both resource availability and costly maintenance functions. The aim of this study is to evaluate the effect of habitat quality on proinflammatory response to phytohemagglutinin (PHA) in Tree Swallows (Tachycineta bicolor (Vieillot, 1808)) under contrasting agricultural practices. Specifically, we tested the hypothesis that lower quality habitat (intensive agricultural practices and low temperature) negatively impairs immune responses. To do so, we compared the response to PHA of adult female and nestling Tree Swallows nesting in intensive vs. nonintensive agricultural landscapes over 3 years (2008–2010). In accordance with our predictions, we found that habitat quality affected adult female responses to PHA. The response of adult females was significantly higher in nonintensive agricultural areas than in intensive ones. The level of agricultural intensity, however, had no influence on the response to PHA of nestlings. Our results suggest that female adults can buffer the negative impact of a low-quality habitat on their nestlings. Furthermore, our results suggest that under limiting conditions, individuals may have to trade between immunity and other functions such as parental effort.


1991 ◽  
Vol 69 (10) ◽  
pp. 2540-2547 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Joanna Leary ◽  
Caragh Fitzgerald

We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.


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