Clutch size: a major sex ratio determinant in fig pollinating wasps?

2005 ◽  
Vol 328 (5) ◽  
pp. 471-476 ◽  
Author(s):  
Finn Kjellberg ◽  
Judith L. Bronstein ◽  
Glen van Ginkel ◽  
Jaco M. Greeff ◽  
Jamie C. Moore ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Clutch Size

scholarly journals Differential allocation in relation to mate song quality in the Bengalese finch

Behaviour ◽  
2013 ◽  
Vol 150 (13) ◽  
pp. 1491-1508 ◽  
Author(s):  
M. Soma ◽  
K. Okanoya
Keyword(s):  
Sex Ratio ◽  
Clutch Size ◽  
Egg Production ◽  
Reproductive Investment ◽  
Production Performance ◽  
Egg Mass ◽  
Differential Allocation ◽  
Bengalese Finch ◽  
Biased Sex Ratio ◽  
Sexual Traits

Postmating sexual selection plays an important part in the evolution of secondary sexual characters. Based on differential allocation theory that predicts biased reproductive investment of females depending on the attractiveness of mates, a number of previous studies have shown that egg production is related in various ways to ornamental sexual traits of males, but evidence for behavioural sexual traits is less abundant. In this study we examine such maternal effects in relation to birdsong. Because the Bengalese finch is a monomorphic songbird, courtship song serves a key role in mate choice. To take into account individual female differences in egg production performance, we sequentially paired naïve, captive, female Bengalese finches to two different males, and investigated if their reproductive investment (clutch size, egg mass and hatchling sex ratio) was related to the song traits of their mates. We found that clutch size and egg mass were highly repeatable within individual females while sex ratio was not. Despite the inflexibility of egg mass within each female, egg mass increased when females were mated to males with longer songs. In addition, we found a non-significant weak tendency toward male-biased sex ratio in relation to longer song duration of mates. Our findings suggest that females mated to better mates adjusted their reproductive investment by producing heavier eggs and possibly offspring of the more costly sex.

Shared reproduction and sex ratio adjustment to clutch size in a socially polymorphic orchid bee

Ethology ◽  
2019 ◽  
Vol 126 (1) ◽  
pp. 88-96
Author(s):  
Anna Friedel ◽  
H. Michael G. Lattorff ◽  
José Javier G. Quezada‐Euán ◽  
Samuel Boff
Keyword(s):  
Sex Ratio ◽  
Clutch Size ◽  
Orchid Bee ◽  
Sex Ratio Adjustment

scholarly journals Nestling Sex Ratios in the Yellow-Naped Amazon: No Evidence for Adaptive Modification

The Condor ◽  
2002 ◽  
Vol 104 (2) ◽  
pp. 437-440 ◽  
Author(s):  
Jason M. South ◽  
Timothy F. Wright
Keyword(s):  
Sex Ratio ◽  
Clutch Size ◽  
Sex Allocation ◽  
Sex Ratios ◽  
Relative Fitness ◽  
Molecular Sexing ◽  
Hatch Date ◽  
Adaptive Modification ◽  
Regional Dialects ◽  
Fitness Benefits

AbstractMany birds, including some parrots, may adjust the sex ratio of their offspring in relation to the relative fitness benefits of sons and daughters. We investigated nestling sex ratios in Yellow-naped Amazons (Amazona auropalliata) using a molecular sexing technique that amplifies intronic regions of the CHD-W and CHD-Z genes in birds. We examined all nestlings in 37 complete clutches comprising 77 chicks. The overall nestling sex ratio did not differ from unity. Sex allocation was not associated with hatch date, sequence of hatching, or clutch size. We also found no difference in sex ratio between two regional dialects. Female Yellow-naped Amazons may be unable to control their hatchling sex ratio. Alternatively, there may be no fitness benefits to females producing more of one sex in relation to the factors we measured here.No Existe Evidencia que Indique Modificaciones Adaptativas de la Proporción de Sexos en la Progenie de Amazona auropalliataResumen. En muchas aves, incluyendo los loros, la proporción de sexos en la progenie puede ajustarse en relación a los beneficios relativos de adecuación biológica de hembras y machos. Dichas tasas fueron investigadas en Amazona auropalliata por medio de una técnica molecular de determinación sexual por la cual se amplifican regiones intrónicas de los genes CHD-W y CHD-Z de aves. Se examinaron todos los pichones de 37 nidadas completas, constituidas por 77 pichones. La proporción de sexos total no resultó diferente a uno. La asignación sexual no estuvo correlacionada con la fecha de eclosión, la secuencia de eclosión, ni el tamaño de la nidada. Tampoco se encontraron diferencias en las proporciones de sexos entre dos dialectos vocales regionales. Las hembras de A. auropalliata podrían no tener la habilidad de controlar la proporción de sexos de su progenie. Alternativamente, es posible que en términos de adecuación biológica, no haya diferencia en el beneficio de producir una progenie enriquecida en un sexo determinado con respecto a los factores medidos en este estudio.

Parturition and clutch characteristics of short-horned lizards (Phrynosoma douglassii brevirostre) from Alberta

1991 ◽  
Vol 69 (11) ◽  
pp. 2759-2764 ◽  
Author(s):  
G. Lawrence Powell ◽  
Anthony P. Russell
Keyword(s):  
Sex Ratio ◽  
Clutch Size ◽  
Female Age ◽  
Physiological Cost ◽  
Short Period ◽  
Horned Lizards ◽  
Female Behaviour ◽  
Extraembryonic Membranes ◽  
Clutch Mass

Field capture records and observation of wild-caught females indicate that parturition in Alberta populations of Phrynosoma douglassii brevirostre, a viviparous lizard, is synchronized among females, taking place during a short period around the end of July, and generally around noon. Relative clutch mass appears to decrease with female age, and clutch size varies between 6 and 11 neonates, with an overall sex ratio of 1.0. Female behaviour during parturition consists of four distinct phases, involving straddling of the hind legs, abdominal contractions, and pelvic movements. After parturition, the female moves away from the neonate. Neonate behaviour is associated chiefly with escaping from the extraembryonic membranes. Male neonates have a greater snout–vent length than females, but neonate mass is similar. Gravidity appears to impose a great physiological cost upon reproducing females.

The influence of host quality on progeny and sex allocation in the pupal ectoparasitoid,Muscidifurax raptorellus(Hymenoptera: Pteromalidae)

1998 ◽  
Vol 88 (3) ◽  
pp. 299-304 ◽  
Author(s):  
J.A. Harvey ◽  
G.J.Z. Gols
Keyword(s):  
Sex Ratio ◽  
Clutch Size ◽  
Adult Development ◽  
Development Time ◽  
Host Quality ◽  
Adult Size ◽  
Female Progeny ◽  
Interspecific Differences ◽  
Adult Parasitoid ◽  
Secondary Sex Ratio

AbstractMuscidifurax raptorellusKogan & Legner is a gregarious pteromalid ectoparasitoid that attacks pupae and pharate adults from several families of the higher Diptera. Egg-to-adult development time, adult parasitoid size and emerging offspring ( = secondary) sex ratio ofM. raptorelluswere compared with clutch size in two hosts that differed greatly in mass, the smallMusca domesticaLinnaeus and the largerCalliphora vomitoriaLinnaeus. The mean number of emerging parasitoids did not vary significantly with host species, although slightly higher clutch sizes were recorded inC. vomitoria. Irrespective of offspring sex, parasitoids completed development more rapidly inM. domesticathan inC. vomitoria. In the small host, the development time and adult size ofM. raptorelluswere negatively correlated with clutch size. By contrast, female parasitoid size was unaffected by clutch size in the larger host,C. vomitoria. In both hosts, female parasitoids were significantly larger than male parasitoids. The secondary sex ratio (percentage males) of emerging parasitoids was significantly lower inC. vomitoria, and varied with clutch size in both hosts. InC. vomitoria, the greatest proportion of females emerged from hosts with the highest clutch sizes, whereas inM. domesticahosts with the highest clutch sizes produced the lowest proportion of female progeny. The results described here show that the development ofM. raptorellusis profoundly affected by interspecific differences in host quality. Our results suggest that mating structure and host quality have potentially different effects on sex ratio decisions inM. raptorellus, and perhaps other gregarious parasitoids.

scholarly journals Brood size and sex ratio in response to host quality and wasp traits in the gregarious parasitoidOomyzus sokolowskii(Hymenoptera: Eulophidae)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2919 ◽  
Author(s):  
Xianwei Li ◽  
Liangting Zhu ◽  
Ling Meng ◽  
Baoping Li
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Clutch Size ◽  
Brood Size ◽  
Linear Trend ◽  
Offspring Sex Ratio ◽  
Host Body ◽  
Larval Host ◽  
Host Instar ◽  
Host Body Size

This laboratory study investigated whether the larval-pupal parasitoidOomyzus sokolowskiifemales adjust their brood size and sex ratio in response to body size and stage ofPlutella xylostellalarval hosts, as well as to their own body size and the order of oviposition. These factors were analyzed using multiple regression with simultaneous entry of them and their two-way interactions. Parasitoids brood size tended to increase with host body size at parasitism when the 4th instar larval host was attacked, but did not change when the 2nd and 3rd instar larvae were attacked. Parasitoids did not vary in brood size according to their body size, but decreased with their bouts of oviposition on a linear trend from 10 offspring adults emerged per host in the first bout of oviposition down to eight in the third. Parasitoid offspring sex ratio did not change with host instar, host body weight, wasp body size, and oviposition bout. Proportions of male offspring per brood were from 11% to 13% from attacking the 2nd to 4th instar larvae and from 13% to 16% across three successive bouts of oviposition, with a large variation for smaller host larvae and wasps. When fewer than 12 offspring were emerged from a host, one male was most frequently produced; when more than 12 offspring were emerged, two or more males were produced. Our study suggests thatO. sokolowskiifemales may optimize their clutch size in response to body size of matureP. xylostellalarvae, and their sex allocation in response to clutch size.

Hatching order and sex ratio in Southern Grey ShrikeLanius meridionalisin relation to clutch size

Ibis ◽  
2016 ◽  
Vol 159 (1) ◽  
pp. 230-234
Author(s):  
Gregorio Moreno-Rueda ◽  
Francisco Campos ◽  
Francisco Gutiérrez-Corchero ◽  
María Ángeles Hernández
Keyword(s):  
Sex Ratio ◽  
Clutch Size ◽  
Hatching Order
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