Don't put all your eggs in small baskets: Ineffective guardians, incidence of parasitoids and clutch size of Latrodectus geometricus (Araneae, Theridiidae) along an urban gradient

Author(s):  
Rafael Rios Moura ◽  
Agostinho Tozzo Neto ◽  
Marcelo Oliveira Gonzaga

2014 ◽  
Vol 113 (2) ◽  
pp. 100-102
Author(s):  
Douglas W. R. Danielsen ◽  
Daniel E. Clarke ◽  
Stephen J. Valle ◽  
Amy A. Ansalmo ◽  
Leonard S. Vincent ◽  
...  


Author(s):  
Madi P. Vasquez ◽  
Rebekah J. Rylander ◽  
Jacquelyn M. Tleimat ◽  
Sarah Fritts

Numerous avian species use anthropogenic materials in constructing nests, particularly in urbanized environments. Anthropogenic materials, including plastics, have been demonstrated to have both beneficial and harmful effects on survival and reproduction. During the spring of 2018, we collected 45 Black-crested Titmouse Baeolophus atricristatus nests in San Marcos, TX, U.S. with two objectives: 1) assess and compare the mass and proportion of nest materials along an urban gradient, and 2) examine the relationship between nest materials, clutch size, and hatching success. We categorized each nest based on collection location as either urban, residential, park or rural and separated nest materials into six categories: leaves, snakeskin, twigs, moss, plastic, and non-plastic artificial materials. We then compared raw mass and proportion of mass of each nest material among urbanization categories. Nests in the urban category were 1.6-1.9 times lighter in mass than nests in other locations along the urban gradient (p = 0.01) and contained 4-5 times greater proportion, but not mass, of plastic compared to nests in all other locations. Nests in residential areas contained the greatest mass of combined anthropogenic materials. Neither clutch size nor hatching success differed based on urbanization category, nest mass, or proportions of anthropogenic or natural nest materials. The differences in mass of nests and increased proportion of plastics could have been due to a lack of natural nesting materials however, we did not estimate availability of nesting materials at any location. Results add to the growing literature that the use of anthropogenic materials in nests varies across an urban gradient, and the effect of anthropogenic materials on nesting parameters varies among species.



1987 ◽  
Vol 130 (6) ◽  
pp. 839-863 ◽  
Author(s):  
R. F. Rockwell ◽  
C. S. Findlay ◽  
F. Cooke


Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.



2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cynthia Reséndiz-Infante ◽  
Gilles Gauthier

AbstractMany avian migrants have not adjusted breeding phenology to climate warming resulting in negative consequences for their offspring. We studied seasonal changes in reproductive success of the greater snow goose (Anser caerulescens atlantica), a long-distance migrant. As the climate warms and plant phenology advances, the mismatch between the timing of gosling hatch and peak nutritive quality of plants will increase. We predicted that optimal laying date yielding highest reproductive success occurred earlier over time and that the seasonal decline in reproductive success increased. Over 25 years, reproductive success of early breeders increased by 42%, producing a steeper seasonal decline in reproductive success. The difference between the laying date producing highest reproductive success and the median laying date of the population increased, which suggests an increase in the selection pressure for that trait. Observed clutch size was lower than clutch size yielding the highest reproductive success for most laying dates. However, at the individual level, clutch size could still be optimal if the additional time required to acquire nutrients to lay extra eggs is compensated by a reduction in reproductive success due to a delayed laying date. Nonetheless, breeding phenology may not respond sufficiently to meet future environmental changes induced by warming temperatures.



Author(s):  
Mary S. Fleck ◽  
Maude Dinan ◽  
Lauren J. Simmons ◽  
Todd D. Steury ◽  
Christopher A. Lepczyk


Copeia ◽  
1968 ◽  
Vol 1968 (2) ◽  
pp. 417 ◽  
Author(s):  
Allen E. Greer
Keyword(s):  


Ibis ◽  
2021 ◽  
Author(s):  
David Diez‐Méndez ◽  
Juan José Sanz ◽  
Emilio Barba




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