Prevalence and intensity of hematozoan infections in a population of American kestrels

1999 ◽  
Vol 77 (1) ◽  
pp. 162-170 ◽  
Author(s):  
Russell D Dawson ◽  
Gary R Bortolotti
Keyword(s):  
Breeding Season ◽  
Parasite Load ◽  
Chronic Infections ◽  
Age Classes ◽  
Sexually Selected Traits ◽  
Several Variables ◽  
American Kestrels ◽  
Selected Traits ◽  
Breeding Seasons ◽  
Host Parasite

Interest in hematozoan parasites has been considerable in recent years, mostly as a result of Hamilton and Zuk's idea that parasites influence the expression of sexually selected traits. However, little is known about the basic patterns of parasitism and the dynamics of host-parasite relationships. We describe the patterns of blood parasitism in American kestrels (Falco sparverius) sampled throughout the breeding seasons of 1994 and 1995, and investigate the influence of several variables on parasite load. Parasite prevalences in kestrels were high, ranging from 75 to 94% depending on the sex of the birds and stage of the breeding season. Prevalence increased with date, indicating either active parasite transmission or relapses of chronic infections. Parasite intensity also increased with date, but these effects were sex- and year-specific. We detected no sex differences in either prevalence or intensity, but prevalences were higher in young (second calendar year) birds than in older birds. Because this effect was evident early in the breeding season, we suggest that it was due to differential recrudescence of chronic infections between age-classes. Food supply had no effect on parasite load. Among birds that were sampled twice in the same year, parasite status remained relatively constant, although some birds acquired infections while others lost them. Change in intensity between samples was dependent on year; nonetheless, intensities remained relatively stable throughout the breeding season. Kestrels sampled in both years had consistent parasite loads. Parasites were detected in only 3% of kestrel nestlings.

Female preference and male nuptial colouration in the freshwater fish Gobiomorphus breviceps: geographic variation among populations

1999 ◽  
Vol 77 (3) ◽  
pp. 463-469 ◽  
Author(s):  
William J Hamilton ◽  
Robert Poulin
Keyword(s):  
Environmental Factors ◽  
Freshwater Fish ◽  
Geographic Variation ◽  
Parasite Load ◽  
Water Clarity ◽  
Female Mate Choice ◽  
Local Conditions ◽  
Sexually Selected Traits ◽  
Different Populations ◽  
Selected Traits

Geographic variation in the strength or direction of sexual selection acting on different populations has been documented before but has not been the subject of intense study. We examine covariation among sexually selected traits and environmental factors for five stream populations of a small New Zealand freshwater fish, the upland bully, Gobiomorphus breviceps (Eleotridae). Levels of infection by a trematode parasite and some aspects of female behaviour and male colouration varied significantly among populations. Among individual fish we found that female mate choice behaviours and male colouration did not correlate similarly with other traits, or with parasite load, in the different populations studied. We also determined whether average population values correlated among the different stream populations. Whereas environmental factors such as water clarity and substrate colouration appeared to be unimportant, average parasite load correlated with some components of male colouration, and female preferences appeared to be correlated with male colouration. These results illustrate both the variability among populations that prevents results obtained from one population from being generalized to the entire species, and the plasticity of sexually selected traits in relation to local conditions.

scholarly journals Evidence for use of both capital and income breeding strategies in the mangrove tree crab, Aratus pisonii

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jade Carver ◽  
Morgan Meidell ◽  
Zachary J. Cannizzo ◽  
Blaine D. Griffen
Keyword(s):  
Breeding Season ◽  
Breeding Strategy ◽  
Reproductive Period ◽  
Breeding Strategies ◽  
Mangrove Tree ◽  
Income Breeding ◽  
Aratus Pisonii ◽  
Breeding Seasons ◽  
And Storage ◽  
Capital And Income Breeding

AbstractTwo common strategies organisms use to finance reproduction are capital breeding (using energy stored prior to reproduction) and income breeding (using energy gathered during the reproductive period). Understanding which of these two strategies a species uses can help in predicting its population dynamics and how it will respond to environmental change. Brachyuran crabs have historically been considered capital breeders as a group, but recent evidence has challenged this assumption. Here, we focus on the mangrove tree crab, Aratus pisonii, and examine its breeding strategy on the Atlantic Florida coast. We collected crabs during and after their breeding season (March–October) and dissected them to discern how energy was stored and utilized for reproduction. We found patterns of reproduction and energy storage that are consistent with both the use of stored energy (capital) and energy acquired (income) during the breeding season. We also found that energy acquisition and storage patterns that supported reproduction were influenced by unequal tidal patterns associated with the syzygy tide inequality cycle. Contrary to previous assumptions for crabs, we suggest that species of crab that produce multiple clutches of eggs during long breeding seasons (many tropical and subtropical species) may commonly use income breeding strategies.

Tests of the positive and functional allometry hypotheses for sexually selected traits in the Jamaican field cricket

2021 ◽  
pp. 104413
Author(s):  
Susan M. Bertram ◽  
Danya D. Yaremchuk ◽  
Mykell L. Reifer ◽  
Amy Villareal ◽  
Matthew J. Muzzatti ◽  
...  
Keyword(s):  
Field Cricket ◽  
Sexually Selected Traits ◽  
Selected Traits

scholarly journals Sexually Selected Traits: A Fundamental Framework for Studies on Behavioral Epigenetics

ILAR Journal ◽  
2012 ◽  
Vol 53 (3-4) ◽  
pp. 253-269 ◽  
Author(s):  
E. Jasarevic ◽  
D. C. Geary ◽  
C. S. Rosenfeld
Keyword(s):  
Sexually Selected Traits ◽  
Selected Traits

scholarly journals Density and Flock Size of the Raven (Corvus corax) In the Orawa - Nowy Targ Basin During Non-Breeding Season

Ring ◽  
2006 ◽  
Vol 28 (2) ◽  
pp. 119-125
Author(s):  
Michał Ciach ◽  
Dominik Wikar ◽  
Małgorzata Bylicka
Keyword(s):  
Breeding Season ◽  
Early Spring ◽  
Food Resources ◽  
High Density ◽  
Line Transect ◽  
Flock Size ◽  
Early Winter ◽  
Corvus Corax ◽  
Line Transect Method ◽  
Breeding Seasons

Density and Flock Size of the Raven (Corvus corax) In the Orawa - Nowy Targ Basin During Non-Breeding Season During the 2002/2003-2004/2005 non-breeding seasons the density of the Raven in the open habitats of the Orawa - Nowy Targ Basin was studied by line transect method. The results were analysed in four periods (autumn, early winter, winter and early spring). The median density of Ravens did not differ significantly between individual periods and was respectively: 3.5, 3.8, 4.8 and 3.8 indiv. / 10 km. Number of birds during particular controls varied from 1.0 to 24.8 indiv. / 10 km. However, while excluding flocks, the median density of single individuals and pairs of the Raven was considerably lower and in subsequent periods reached respectively: 2.2, 2.4, 2.2 and 1.7 indiv. / 10 km. Flock size did not differ significantly between individual periods. Single individuals and, less often, groups of two birds were recorded mostly. Small (3-5 indiv.) and medium (6-15 indiv.) flocks were recorded rarely and large flocks (16 indiv. and above) - only exceptionally. The high density and strong fluctuations of abundance of Ravens were determined by flocks presence, which was probably linked to irregular occurrence of food resources.

scholarly journals Erythraeid larvae parasitizing dragonflies in Zambia—description of Leptus (Leptus) chingombensis sp. nov. with data on biology and ecology of host-parasite interactions

2019 ◽  
Vol 24 (5) ◽  
pp. 790
Author(s):  
Rafał Bernard ◽  
Magdalena Felska ◽  
Joanna Mąkol
Keyword(s):  
Dna Barcode ◽  
Morphological Characteristics ◽  
Parasite Load ◽  
Ventral Side ◽  
Habitat Conditions ◽  
Local Character ◽  
Host Parasite Interactions ◽  
Group Variation ◽  
The Common ◽  
Host Parasite

A survey of odonate fauna in Zambia (Central Province, Luano District) resulted in discovery of ectoparasitic larvae of Leptus (L.) chingombensis sp. nov. (Trombidiformes: Parasitengona, Erythraeidae) on four species of dragonflies (Odonata) representing four different families assigned to Zygoptera and Anisoptera. The morphological characteristics of the new species is supported with DNA barcode sequence. Despite some intra-group variation related to relatively large sample, the morphological and genetic consistence confirm the common specific identity of the material. A brief comparison of Leptus spp. hitherto known from the Afrotropic as larvae is given. Supplementary data to the descriptions of Leptus (L.) bicristatus Fain et Elsen, 1987, Leptus (L.) aldonae Haitlinger, 1987 and Leptus (L.) soddagus Haitlinger, 1990, based on examination of type material, are provided. In the case of L. (L.) chingombensis sp. nov., the parasite load reached high, previously not recorded for Odonata–terrestrial Parasitengona association values, attaining at 44 and 49 larvae. Clear topic preferences towards the ventral side of the host’s body were recorded, with an additional tendency to distal parts of synthorax and the ventral depression of the abdomen. We hypothesize that the infestation did not take place synchronously at dragonflies emergence, but consisted in repeated infestation events during the recurrent appearance of dragonflies in the contact microhabitat occupied by Leptus. The very local character of the finding along with the regular appearance of larvae parasitizing dragonflies, obviously favoured by specific habitat conditions, no doubts confirms the non-accidental nature of the phenomenon.

scholarly journals Investigating post-breeding moult locations and diets of Common Guillemots (Uria aalge) in the North Sea using stable isotope analyses

2020 ◽  
Author(s):  
Alec P. Christie
Keyword(s):  
Stable Isotope ◽  
Breeding Season ◽  
North Sea ◽  
Cost Effective ◽  
Uria Aalge ◽  
Age Classes ◽  
Stable Isotope Analyses ◽  
The North ◽  
The North Sea ◽  
Isotope Analyses

AbstractSeabird movements and diet during the non-breeding season are poorly studied, yet understanding these aspects of seabird ecology is extremely important to effectively conserve these protected species. Stable isotope analyses (SIA) provide a cost-effective solution to filling these knowledge gaps, yielding information on diet and foraging locations of animals. This study aimed to use SIA to investigate whether Common Guillemots (Uria aalge) from different age classes and locations in the UK had contrasting diets and foraging areas during the post-breeding moult (July-September). SIA of secondary feathers and a newly-developed North Sea isoscape were used to identify the likeliest foraging areas and diets of deceased guillemots recovered from beaches in eastern Scotland and mixed fisheries in Cornwall and the Celtic Sea. Overall, guillemots foraged widely in the western, eastern and southern North Sea, consuming a variety of clupeid, gadoid and invertebrate prey. There were negligible dietary differences between age classes and birds from different recovery locations. Juveniles showed a wider range in foraging areas, but both age classes foraged in similar parts of the North Sea. Guillemots recovered from Scotland may have foraged further north, only overlapping with guillemots recovered from the southwestern UK in the southern and eastern North Sea. Their winter recovery locations also implied that they exhibited different movement strategies during the non-breeding season, meriting further investigation. Conservation efforts should target foraging areas in the southern and eastern North Sea which are highly threatened by gillnet fishing, shipping traffic and oil infrastructure.

Phenotypic plasticity of the montane vole (Microtus montanus) in unpredictable environments

1992 ◽  
Vol 70 (11) ◽  
pp. 2121-2124 ◽  
Author(s):  
Norman C. Negus ◽  
Patricia J. Berger ◽  
Aelita J. Pinter
Keyword(s):  
Phenotypic Plasticity ◽  
Breeding Season ◽  
Growth Rates ◽  
Adaptive Strategy ◽  
Severe Drought ◽  
Microtus Montanus ◽  
Age Cohort ◽  
Montane Meadow ◽  
Study Sites ◽  
Breeding Seasons

From 1987 to 1989, the cohort dynamics of Microtus montanus populations were studied at two montane meadow sites approximately 160 km apart, in northwestern Wyoming. The 1987 and 1988 breeding seasons differed markedly from each other. In 1987, melt off occurred in April, and the first cohort was born in May (cohort 1). The entire breeding season was favorable owing to frequent rainfall throughout the summer. Cohort 1 animals grew rapidly and females began breeding at 4–5 weeks of age. Likewise, cohort 2 (June) animals exhibited rapid growth and females were breeding at 7–8 weeks of age. Cohort 3 (July and August) animals grew more slowly and most entered the winter as prepubertal animals of subadult size. At the end of the summer, cohort 3 animals represented >70% of the voles recruited during the breeding season. In 1988, following melt off in late April, precipitation was below normal and the situation intensified to severe drought through the summer. The growth rates of cohort 1 and 2 animals were significantly lower than 1987 growth rates, and very few females attained sexual maturity. At the end of the summer, cohort 3 animals represented <25% of the total recruitment at both study sites. Such apparent phenotypic plasticity of growth and maturation appears to be an evolved adaptive strategy that is responsive to several environmental cues. Both study sites, although widely separated, exhibited virtually identical patterns throughout the study.

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