Brood Size and Offspring Age Affect Risk-Taking and Aggression in Nest-Guarding Common Gobies

Behaviour ◽  
1993 ◽  
Vol 125 (3-4) ◽  
pp. 233-243 ◽  
Author(s):  
Klaus Vestergaard ◽  
Carin Magnhagen
Keyword(s):  
Parental Care ◽  
Risk Taking ◽  
Brood Size ◽  
Male Body ◽  
Male Size ◽  
Zoarces Viviparus ◽  
The Common ◽  
Egg Developmental Stage ◽  
Time Away ◽  
Common Goby

AbstractThe importance of brood size, offspring age, and male size for parental care behaviour was studied in the common goby, Pomatoschistus microps. In field observations, the aggression of nest guarding males was measured as attacks towards a finger when disturbing the nest. Attacking males had larger and more developed clutches compared to non-attacking males, but did not differ in body size. In another set of observations nest guarding males were exposed to a predator (eelpout, Zoarces viviparus) and subsequently chased away from their nests. Time away from the nest decreased significantly with egg developmental stage, i.e. with the time the male had spent guarding a particular brood. However, no correlations with male body length or numbers of eggs in the nest were found. We conclude that male common gobies evaluate future reproductive success by using brood age and brood size as cues for making decisions about risk-taking and aggressive behaviour during parental care.

scholarly journals Brood Sex Ratios are Related to Male Size but not to Attractiveness in Common Yellowthroats (Geothlypis Trichas)

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 176-184 ◽  
Author(s):  
Betsy Abroe ◽  
Julia C. Garvin ◽  
Marc C. Pedersen ◽  
Linda A. Whittingham ◽  
Peter O. Dunn
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Reproductive Value ◽  
Male Body ◽  
Male Size ◽  
Common Yellowthroat ◽  
Geothlypis Trichas ◽  
The Common ◽  
Fitness Benefits ◽  
Male Ornament

Abstract When the reproductive value of sons differs from that of daughters, selection will favor broods biased toward the sex that can provide greater fitness benefits. In species where female choice is based on male ornamentation, females mated to highly ornamented males may experience a reproductive advantage by skewing the brood sex ratio toward sons. In the Common Yellowthroat (Geothlypis trichas), males with larger black facial masks are more likely to gain a social mate and sire extrapair young and, as a result, have increased seasonal reproductive success. Females mated to larger-masked males could benefit if they produced more sons. Given that larger- masked males are preferred as extrapair sires, females may also benefit by producing more extrapair sons. We tested these hypotheses during a five-year study of Common Yellowthroats in Wisconsin. Contrary to our predictions, females did not produce more sons when mated to males with larger masks, and extrapair young were not more likely to be male. However, sons were more likely to be sired by males with longer tarsi, which suggests that females may respond to male body size rather than to male ornament size. El Cociente de Sexos en las Nidadas Está Relacionado con el Tamaño de los Machos pero no con el Atractivo en Geothlypis trichas

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.

Sex differences in parental care in the common swift (Apus apus): effect of brood size and nestling age

1998 ◽  
Vol 76 (7) ◽  
pp. 1382-1387 ◽  
Author(s):  
Claudio Carere ◽  
Enrico Alleva
Keyword(s):  
Sex Differences ◽  
Parental Care ◽  
Brood Size ◽  
Energy Requirements ◽  
Mediterranean Population ◽  
Parental Behaviour ◽  
Breeding Activity ◽  
The Common ◽  
Meal Delivery

We analysed sex differences in parental behaviour in a Mediterranean population of common swifts (Apus apus). Females attended the nest and fed the chicks at a higher rate than males and were more in contact with the nestlings during the first days after hatching, while no sex differences were found in other parameters measured. For larger broods no quantitative sex differences were observed in meal-delivery and brooding time, while for small broods the rate of feeding by males was lower than the rate of feeding by females, and males attended the nest less than females. No sex differences were observed at the early nestling stage, but males attended the nest less than females later in the nestling stage. No extra-pair breeding activity was observed. These results suggest that males reduce parental care when the energy requirements of the chicks decrease, while females do not.

Acute effects of pyrene on the common goby pomatoschistus microps (Teleostei, Gobiidae)

2010 ◽  
Vol 196 ◽  
pp. S127-S128
Author(s):  
M. Oliveira ◽  
L.R. Vieira ◽  
C. Gravato ◽  
L. Guilhermino
Keyword(s):  
Acute Effects ◽  
The Common ◽  
Common Goby

Field Observations on the Common Striped Possum (Dactylopsila Trivirgata) in North Queensland.

1996 ◽  
Vol 23 (6) ◽  
pp. 755 ◽  
Author(s):  
KA Handasyde ◽  
RW Martin
Keyword(s):  
Body Weight ◽  
Home Range ◽  
Foraging Behaviour ◽  
Male Body ◽  
Radio Tracking ◽  
Minimum Convex Polygon ◽  
Far North ◽  
Large Trees ◽  
The Common ◽  
Primary Habitat

Habitat utilisation and foraging behaviour by the common striped possum (Dactylopsila trivirgata) was investigated by means of spotlighting and radio-tracking at Shiptons Flat, far north Queensland. Vine forest was the primary habitat of D. trivirgata; however, animals were also observed in open eucalypt (Eucalyptus tereticornis) woodland. Information collected on foraging behaviour suggests that D. trivirgata are generalist insectivores consuming some fruit and other foodstuffs, such as honey. Radio-tracking data were used to calculate the home-range areas of two subadult males. The home range of the smaller male (body weight 290 g) was 5.2 ha (by the 95% harmonic mean (HM) method) or 6.5 ha (by the minimum convex polygon (MCP) method), and that of the larger male (body weight 415 g) was 21.2 ha (95% HM) or 21.3 ha (MCP). Large trees with hollows, which are utilized for denning, appear to be an important feature of the habitat for this species. D. trivirgata exhibits a pronounced degree of sociality and may breed seasonally. Observations suggest that amethystine pythons (Morelia amethistina) may be major predators of D. trivirgata at Shiptons Flat.

scholarly journals Offspring telomere length in the long lived Alpine swift is negatively related to the age of their biological father and foster mother

2017 ◽  
Vol 13 (9) ◽  
pp. 20170188 ◽  
Author(s):  
François Criscuolo ◽  
Sandrine Zahn ◽  
Pierre Bize
Keyword(s):  
Parental Care ◽  
Telomere Length ◽  
Brood Size ◽  
Foster Parents ◽  
Growth Conditions ◽  
Early Growth ◽  
Foster Mother ◽  
Biological Father ◽  
Accumulation Of Damage ◽  
Older Males

A growing body of studies is showing that offspring telomere length (TL) can be influenced by the age of their parents. Such a relationship might be explained by variation in TL at conception (gamete effect) and/or by alteration of early growth conditions in species providing parental care. In a long-lived bird with bi-parental care, the Alpine swift ( Apus melba ), we exchanged an uneven number of 2 to 4-day-old nestlings between pairs as part of a brood size manipulation. Nestling TL was measured at 50 days after hatching, which allowed investigation of the influence of the age of both their biological and foster parents on offspring TL, after controlling for the manipulation. Nestling TL was negatively related to the age of their biological father and foster mother. Nestling TL did not differ between enlarged and reduced broods. These findings suggest that offspring from older males were fertilized by gametes with shorter telomeres, presumably due to a greater cell division history or a longer accumulation of damage, and that older females may have provided poorer parental care to their offspring.

scholarly journals Financial Twilight Re-Appraisal: Ending the Judicially Created Quagmire of Fiduciary Duties to Creditors

2017 ◽  
Vol 78 (2) ◽  
Author(s):  
Anil Hargovan ◽  
Timothy M. Todd
Keyword(s):  
Risk Taking ◽  
Financial Distress ◽  
The United States ◽  
Corporate Law ◽  
Fiduciary Duty ◽  
Fiduciary Duties ◽  
Financial Interests ◽  
The Common ◽  
Corporate Rescue ◽  
Judicial Recognition

Directors owe fiduciary duties of care and loyalty to their corporations, and by extension to their shareholders. When a corporation approaches or enters insolvency, however, courts have recently found that the fiduciary duty calculus may change. Recognizing that creditors have financial interests similar to those of shareholders at or near insolvency, courts in several countries have extended fiduciary duty protection to creditors on equitable grounds. This trend has led to a state of flux and uncertainty in corporate law. Consequently, courts and commentators are battling to fully comprehend the controversial subject of director fiduciary duties to creditors in various jurisdictions. Due to this jurisprudential flux, unresolved issues include, for example, the core notion that the duty arises when the company enters into an “ill-defined sphere” known as the “zone” or “vicinity” of insolvency. The law is remarkably short of specific judicial guidance as to how directors who engage in commercial risk-taking with a view to corporate rescue should discharge their duties without harming the interests of creditors. Indeed, the debate continues even on the critical doctrinal question of whether such a duty is even needed.This Article uses corporate law in both the United States and Australia as emblematic of the real practical concerns inherent in the expansion of fiduciary duties. Consequently, the Article argues that the judicial recognition of directors’ fiduciary duties to creditors when at or near insolvency is objectionable, both from a policy and a doctrinal standpoint, and that any further attempt to develop the common law in this regard should be jettisoned in favor of reliance upon the existing, or modified, statutory regime aimed at creditor protection during times of financial distress. 

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