Variation in Lifetime Male Fitness in Ipomopsis aggregata: Tests of Sex Allocation Theory

1998 ◽  
Vol 152 (3) ◽  
pp. 338
Author(s):  
Campbell
2021 ◽  
Author(s):  
Abrar A. Aljiboury ◽  
Jannice Friedman

AbstractIn hermaphrodites, the allocation of resources to each sex function can influence fitness through reproductive success and mating success. In wind pollinated plants, sex allocation theory predicts that male fitness increases linearly with investment of resources into male function. However, there have been few empirical tests of this prediction. We experimentally manipulated allocation to male function in Ambrosia artemisiifolia (common ragweed) in a field experiment and measured mating success using genetic assays. We investigated the effects of various morphological traits and flowering phenology on male fitness, and on male and female mate diversity. Our results provide evidence for a linear relation between allocation to male function and fitness. We find earlier onset of male flowering time increases reproductive success, while later onset flowering time increases the probability of mating with diverse individuals. This research is among the first empirical studies testing the prediction of linear male fitness returns in wind pollinated plants. Our results provide insight into the large investment into male function by wind pollinated plants and temporal variation in sex allocation.


Oikos ◽  
2000 ◽  
Vol 91 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Marielle C. J. Rademaker ◽  
Tom J. de Jong

1991 ◽  
Vol 69 (12) ◽  
pp. 2973-2977 ◽  
Author(s):  
Thane Wibbels ◽  
R. Erik Martin ◽  
David W. Owens ◽  
Max S. Amoss Jr.

The sex ratio of immature loggerhead sea turtles, Caretta caretta, inhabiting the Atlantic coastal waters of Florida was investigated. Blood samples were obtained from 223 turtles that were captured in the intake channel of a power plant on Hutchinson Island. A serum androgen sexing technique was utilized to sex individual turtles. The sex ratio of the turtles (2.1 female: 1.0 male) differed significantly from 1:1 and thus appears to differ from predictions of sex allocation theory. These observations are consistent with those of a previous study, and collectively the results suggest that the sex ratio of immature C. caretta inhabiting the Atlantic coastal waters of the United States is significantly female biased: approximately two females per male.


2015 ◽  
Vol 282 (1807) ◽  
pp. 20150389 ◽  
Author(s):  
Penelope R. Whitehorn ◽  
Nicola Cook ◽  
Charlotte V. Blackburn ◽  
Sophie M. Gill ◽  
Jade Green ◽  
...  

Sex allocation theory has proved to be one the most successful theories in evolutionary ecology. However, its role in more applied aspects of ecology has been limited. Here we show how sex allocation theory helps uncover an otherwise hidden cost of neonicotinoid exposure in the parasitoid wasp Nasonia vitripennis . Female N. vitripennis allocate the sex of their offspring in line with Local Mate Competition (LMC) theory. Neonicotinoids are an economically important class of insecticides, but their deployment remains controversial, with evidence linking them to the decline of beneficial species. We demonstrate for the first time to our knowledge, that neonicotinoids disrupt the crucial reproductive behaviour of facultative sex allocation at sub-lethal, field-relevant doses in N. vitripennis . The quantitative predictions we can make from LMC theory show that females exposed to neonicotinoids are less able to allocate sex optimally and that this failure imposes a significant fitness cost. Our work highlights that understanding the ecological consequences of neonicotinoid deployment requires not just measures of mortality or even fecundity reduction among non-target species, but also measures that capture broader fitness costs, in this case offspring sex allocation. Our work also highlights new avenues for exploring how females obtain information when allocating sex under LMC.


2006 ◽  
Vol 2 (2) ◽  
pp. 229-231 ◽  
Author(s):  
Bruce C Robertson ◽  
Graeme P Elliott ◽  
Daryl K Eason ◽  
Mick N Clout ◽  
Neil J Gemmell

Supplementary feeding is often a key tool in the intensive management of captive and threatened species. Although it can increase such parameters as breeding frequency and individual survival, supplementary feeding may produce undesirable side effects that increase overall extinction risk. Recent attempts to increase breeding frequency and success in the kakapo Strigops habroptilus using supplementary feeding inadvertently resulted in highly male-biased chick sex ratios. Here, we describe how the inclusion of sex allocation theory has remedied this conservation dilemma. Our study is the first to manipulate chick sex ratios in an endangered species by altering maternal condition and highlights the importance of incorporating evolutionary theory into modern conservation practice.


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