Intrasexual Aggression and the Mating Behavior of Brown-Headed Cowbirds: Their Relation to Population Densities and Sex Ratios

The Condor ◽  
1989 ◽  
Vol 91 (1) ◽  
pp. 43-51 ◽  
Author(s):  
David A. Yokel
Keyword(s):  
Mating Behavior ◽  
Sex Ratios ◽  
Population Densities ◽  
Intrasexual Aggression

Sex ratios, mating behavior and sexual size dimorphism of the northern water snake, Nerodia sipedon

1995 ◽  
Vol 36 (5) ◽  
pp. 301-311 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Frances E. Barry ◽  
Gregory P. Brown ◽  
Mark R. L. Forbes
Keyword(s):  
Mating Behavior ◽  
Sexual Size Dimorphism ◽  
Sex Ratios ◽  
Nerodia Sipedon ◽  
Size Dimorphism ◽  
Water Snake ◽  
Northern Water Snake

In memoriam: Dr. J. (Hans) van den Assem

2014 ◽  
Vol 64 (2) ◽  
pp. 125-128
Author(s):  
Leo Beukeboom ◽  
John (Jack) Werren
Keyword(s):  
Mating Behavior ◽  
Sex Ratios ◽  
Model Organism ◽  
Behavioral Biology ◽  
Parasitoid Wasps ◽  
University Of Leiden ◽  
In Memoriam ◽  
The University

On 11 April 2014 behavioral biologist Hans van den Assem passed away. As member of the Ethology group at the University of Leiden he has contributed significantly to the blossoming of the field of behavioral biology. Hans was a pioneer in the study of mating behavior of parasitoid wasps, contributed to the development of Nasonia as a hymenopteran model organism, and was among the first to show that parasitoids can adaptively adjust their progeny sex ratios. He has been an inspiring mentor and is best remembered as a “scholar and gentleman”.

Sex ratios, mating behavior and sexual size dimorphism of the northern water snake, Nerodia sipedon

1995 ◽  
Vol 36 (5) ◽  
pp. 301-311 ◽  
Author(s):  
P. J. Weatherhead ◽  
Frances E. Barry ◽  
Gregory P. Brown ◽  
M. R. L. Forbes
Keyword(s):  
Mating Behavior ◽  
Sexual Size Dimorphism ◽  
Sex Ratios ◽  
Nerodia Sipedon ◽  
Size Dimorphism ◽  
Water Snake ◽  
Northern Water Snake

scholarly journals A Neonicotinoid Affects the Mating Behavior of Spalangia endius (Hymenoptera: Pteromalidae), a Biological Control Agent of Filth Flies

2019 ◽  
Vol 48 (3) ◽  
pp. 489-495 ◽  
Author(s):  
Aspen N Kremer ◽  
Bethia H King
Keyword(s):  
Biological Control ◽  
Mating Behavior ◽  
Biological Control Agent ◽  
Sex Ratios ◽  
Parasitoid Wasp ◽  
Sublethal Effect ◽  
Control Agent ◽  
Male Preference ◽  
Spalangia Endius ◽  
Fly Control

Abstract Spalangia endius Walker is a parasitoid wasp that is commercially available as a biological control agent for filth fly pests in livestock-rearing operations. Imidacloprid is often used to control these flies. The present study examined the sublethal effect of field-realistic concentrations of imidacloprid on mating behavior, offspring sex ratios, and male preference for virgin females. After exposure to imidacloprid, S. endius females that survived were less likely to mate than control females, which will result in male-biased sex ratios because only mated females can produce daughters. Males did not avoid exposed females, but exposed females were almost always unreceptive. Males that survived exposure to imidacloprid exhibited reduced mating competitiveness against unexposed males. However, if an exposed male mated, his mate’s sex ratio and ability to control flies was unaffected. Exposed males were also still able to discriminate against mated, and thus usually unreceptive, females. Together with previous studies, these results suggest that not only does imidacloprid reduce the ability of S. endius females to survive and parasitize hosts, but when an exposed female does survive and parasitize hosts, she is likely to produce just sons, because of her lack of receptivity. More-male-biased populations of S. endius will decrease their efficacy for fly control. Thus, the use of imidacloprid along with this parasitoid may be financially inefficient for pest management.

Survival and Reproduction of Nasonia vitripennis (Walk.) at Different Host Population Densities

1966 ◽  
Vol 98 (3) ◽  
pp. 275-281 ◽  
Author(s):  
H. G. Wylie
Keyword(s):  
Musca Domestica ◽  
Sex Ratios ◽  
Host Population ◽  
Population Densities ◽  
Nasonia Vitripennis ◽  
Survival And Reproduction

AbstractFemales of Nasonia vitripennis (Walk.) lived longer, found more hosts, and produced more progeny at high host (housefly, Musca domestica L.) population densities than at lower ones. Because they feed on the fly pupae that they parasitize, the female parasites were able to obtain more food at high host population densities. Starved and unstarved females produced progeny with similar sex ratios. By feeding on parasitized fly pupae when unparasitized ones are scarce, females of N. vitripennis increase their longevity and their ability to oviposit if they subsequently find unparasitized hosts. Females that have fed partly or entirely on parasitized pupae subsequently produce relatively more diapause progeny.

Demographic differences among populations of Northern Map Turtles (Graptemys geographica) in intact and fragmented sites

2009 ◽  
Vol 87 (12) ◽  
pp. 1147-1157 ◽  
Author(s):  
A. M. Bennett ◽  
M. Keevil ◽  
J. D. Litzgus
Keyword(s):  
Growth Rates ◽  
Sex Ratios ◽  
Habitat Alteration ◽  
Population Densities ◽  
Demographic Differences ◽  
Fragmented Habitats ◽  
Habitat Alterations ◽  
Map Turtles ◽  
Graptemys Geographica ◽  
Northern Map Turtle

Habitat fragmentation is a leading cause of reptile declines worldwide. We examined demographic differences between populations of Northern Map Turtles, Graptemys geographica (Le Sueur, 1817), inhabiting intact and fragmented sites along the Trent–Severn Waterway (TSW) in Ontario over two field seasons. We examined population densities, sex ratios, body size, and growth rates in two control sites and two fragmented sites (where the waterway is disrupted by dams). We predicted that population density would be higher in control sites, and that sex ratios would differ among sites. Abundance was greater than expected, but densities could not be compared owing to a lack of recaptures. Sex ratios in control sites were slightly male-biased and were significantly female-biased in fragmented sites. Turtles in fragmented habitats were significantly smaller than those in control habitats. Estimated growth rates of juveniles and males were significantly reduced in fragmented populations compared with controls. We hypothesize that habitat alterations in fragmented sites are differentially affecting demographic classes because of the intersexual niche divergence observed in Map Turtles. We emphasize the need for further research to examine the interactions between habitat alteration and invasive species and the effects they are having on Northern Map Turtle populations.

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