scholarly journals Progeny Fitness of the Mealybug Parasitoid Anagyrus sp. nov. nr. Sinope (Hymenoptera: Encyrtidae) as Affected by Brood Size, Sex Ratio, and Host Quality

2007 ◽  
Vol 90 (4) ◽  
pp. 656-664 ◽  
Author(s):  
Juang-Horng Chong ◽  
Ronald D. Oetting
Keyword(s):  
Sex Ratio ◽  
Brood Size ◽  
Host Quality

Population dynamics of Stenothoe valida Dana, 1852 (Amphipoda, Stenothoidae) at Cheongsapo beach of Busan, Republic of Korea

Crustaceana ◽  
2021 ◽  
Vol 94 (4) ◽  
pp. 413-429
Author(s):  
Ye Ji Lee ◽  
Won Gyu Park
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Sex Ratio ◽  
Brood Size ◽  
Ovigerous Female ◽  
Seasonal Pattern ◽  
Recruitment Rate ◽  
Republic Of Korea ◽  
Female Size ◽  
History Of

Abstract The population dynamics of Stenothoe valida Dana, 1852 were studied at Cheongsapo beach of Busan, Republic of Korea, from March 2019 to March 2020. Sampling was conducted once a month at low tide during spring tides. Specimens were grouped by the cephalic length at 0.025 mm intervals, and classified into four categories: females, ovigerous females, males and juveniles. The sex ratio, defined as females : total males + females, exceeded 0.5 during most of the study period. Brood size was significantly coupled with ovigerous female size. Two to four cohorts appeared at each study period. New cohorts occurred at almost every sampling except in the samples Jun-2, and Nov-2. Life span was estimated at 1-2 months. The juvenile ratio, the ratio of ovigerous females, and the recruitment rate estimated by FiSAT were commonly high in summer and winter. The life history of S. valida was not coupled with water temperature, but had a strong seasonal pattern.

scholarly journals Influence of Plant Host Quality on Fitness and Sex Ratio of the Wheat Stem Sawfly (Hymenoptera: Cephidae)

2005 ◽  
Vol 34 (6) ◽  
pp. 1579-1592 ◽  
Author(s):  
H. A. Cárcamo ◽  
B. L. Beres ◽  
F. Clarke ◽  
R. J. Byers ◽  
H.-h. Mündel ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Host Quality ◽  
Plant Host ◽  
Wheat Stem Sawfly

Variation in the Mating System of a Biparental Cichlid Fish, Cichlasoma Panamense

Behaviour ◽  
1985 ◽  
Vol 95 (3-4) ◽  
pp. 181-197 ◽  
Author(s):  
R.J. Wootton ◽  
T.J. Townshend
Keyword(s):  
Game Theory ◽  
Sex Ratio ◽  
Parental Care ◽  
Attack Rate ◽  
Brood Size ◽  
Cichlid Fish ◽  
Dry Season ◽  
Water Levels ◽  
Time Away ◽  
A Current

AbstractCichlasoma panamense is a biparental, substrate-spawning cichlid which breeds during the dry season in Panamanian streams. In one population some males helped to defend their offspring throughout the period of parental care but many deserted their mates to achieve additional spawnings leaving females to guard alone. The proportion of C. panamense guarding in pairs increased throughout the breeding season. This was associated with an increase in the rate with which parental cichlids attacked potential brood predators and an increase in brood size. The increase in attack rate was due to the crowding of fishes as water levels receded during the dry season and especially to the increasing numbers of newly independent cichlids which congregated in the shallow water areas where C. panamense brood. The sex ratio in the population was strongly biased towards females. Males spent more time away from the brood than females which enabled them to find and spawn with unmated females. The attack rate of females brooding alone was not significantly higher than that of those with mates and their foraging rate not significantly lower although they spent less time away from their brood. In a more productive stream where population density was high, breeding was almost entirely in monogamous pairs. The rate at which parents attacked potential predators was higher, the sex ratio was 1:1 and brood size was large. The male's decision to guard or desert appears to depend on his opportunities for further matings, the ability of the female to guard alone and the value of a current brood. These results agree with the predictions of game theory models of parental care.

Sign in / Sign up

Export Citation Format

Share Document