Providing chicks with extra food lowers male but not female provisioning in the House Sparrow Passer domesticus

We assessed whether adult House Sparrows Passer domesticus adjusted their provisioning in response to an experimental increase in the nutritional condition of their nestlings. When we supplemented chicks directly with additional food, male parents, but not female parents, reduced their provisioning. The results for males, but not females, run contrary to a previous experiment in this species. In addition, female provisioning was positively associated with both brood size and the age of the brood. In contrast, whereas male provisioning was positively associated with brood size, males did not increase provisioning as their chicks grew older. Males, but not females, exhibited repeatability in their provisioning. Food supplementation had a larger positive effect upon nestling survival in smaller broods than in larger broods. Overall, there appear to be fundamental differences between males and females in how decisions regarding the level of parental investment in the current brood are made.     

Does body size influence nest attendance? A comparison of Ross’s geese (Chen rossii) and the larger, sympatric lesser snow geese (C. caerulescens caerulescens)

The body-size hypothesis predicts that nest attendance is positively related to body size among waterfowl and that recess duration is inversely related to body size. Several physiological and behavioral characteristics of Ross’s geese (Chen rossii) suggest that females of this species should maintain high nest attendance despite their relatively small body size. Accordingly, we used 8-mm films to compare the incubation behavior of Ross’s geese to that of the larger, closely-related lesser snow geese (C. caerulescens caerulescens; hereafter, snow geese) nesting sympatrically at Karrak lake, Nunavut, Canada in 1993. We found that nest attendance averaged 99% for both species. Our results offer no support for the body-size hypothesis. We suggest that temperature requirements of embryos in relation to short incubation duration and a low foraging efficiency of females select for high nest attendance in both snow geese and Ross’s geese.     

An observational and brood-exchange sudy of paternal provisioning in the red-winged blackbird, Agelaius phoeniceus

Male red-winged blackbirds (Agelaius phoeniceus) provisioned50%(118/235) of available broods over an 8-year period. In mostcases, each male provisioned only the oldest brood on his territory,but in 21 cases, the male fed a younger brood after first feedingan older one. In 10 of these cases the switch to the youngerbrood followed predation of the older brood, but in the remaining11 cases the cause of the switch was unknown. To determine whethermale red-winged blackbirds adjust their provisioning when thedemands of their broods change, we exchanged broods betweenpairs of nests on 10 territories. Before each exchange, eachmale had been feeding nestlings of only one of the two broods.In response to the exchanges, male (and female) red-winged blackbirdsimmediately adjusted their rates of provisioning to the increasedor decreased demands of the broods. In addition, most malesswitched their provisioning within a day after the exchangeso that they fed the same broods as before the exchanges. Ourresults show that male red-winged blackbirds adjust their provisioningwhen the demands of their broods change and suggest that maleshave enough information about other nesting attempts on theirterritories to shift to a more profitable brood when the expectedbenefits of provisioning change. Male red-winged blackbirdsdo not appear to follow an investment strategy based on priorinvestments (i.e., they do not commit the "Concorde fallacy").     

Altruistic cooperation during foraging by the Ache, and the evolved human predisposition to cooperate

This paper presents quantitative data on altruistic cooperation during food acquisition by Ache foragers. Cooperative activities are defined as those that entail a cost of time and energy to the donor but primarily lead to an increase in the foraging success of the recipient. Data show that Ache men and women spend about 10% of all foraging time engaged in altruistic cooperation on average, and that on some days they may spend more than 50% of their foraging time in such activities. The most time-consuming cooperative activity for both sexes is helping during the pursuit of game animals, a pattern that is probably linked to the widespread sharing of game by Ache foragers. Cooperative food acquisition and subsequent food redistribution in hunter-gatherer societies are critical behaviors that probably helped shape universal, evolved, cooperative tendencies that are well illustrated in modern experimental economics. This paper was originally presented at a Max Planck symposium on cooperation in Leipzig in June 1999. This work was partially funded by a grant from the L.S.B. Leakey Foundation and NSF grant BNS 9727656. Kim Hill is a professor of anthropology in the Human Evolutionary Ecology (HEE) program at the University of New Mexico. His primary research interests include hunter-gatherer behavioral ecology, life history theory, food acquisition strategies, food sharing, cooperation, and biodiversity conservation in lowland South America. He has done fieldwork with Nahautl, Ache, Guarani, Hiwi, Mashco Piro, Matsiguenga, and Yora indigenous peoples of Central and South America.     

Experimentally-elevated testosterone, female parental care, and reproductive success in a songbird, the Dark-eyed Junco (Junco hyemalis)

In male dark-eyed juncos (Junco hyemalis), experimentally elevated testosterone (T) decreases male parental care and offspring survival, but results in higher overall fitness through greater mating success. To help address the ensuing question of what prevents selection from favoring higher levels of T in male juncos, we manipulated T in female juncos. A previous study demonstrated no effect of experimentally elevated T on female incubation behavior, suggesting that female parental behavior might be insensitive to T. In this study we asked whether experimentally elevated T mediates other female parental behaviors and whether variation in T-mediated parental behavior might influence reproductive success. We videotaped free-living control- and T-females during nesting to quantify brooding behavior when young were 3 days old and provisioning behavior when young were 6 days old. Nest defense was measured by quantifying responses to a mounted predator placed near the nest. Reproductive success was assessed via fecundity, nestling quality, and nest survival. T-females spent less time than control females brooding but did not differ in provisioning rate. T-females performed fewer dives at the predator mount and, unlike controls, failed to increase defense as nesting progressed. T-females also had lower daily nest survival and lower nest success (odds of producing at least one fledgling). We conclude that some aspects of female parental behavior are sensitive to experimentally elevated T while others are not and consider the implications for the evolution of T-mediated characters in both sexes.     

Gross Anatomy and Histology of the Hook and Skin of Forehead Brooding Male Nurseryfish, Kurtus Gulliveri, From Northern Australia

Mature males of nurseryfish have a hook on their head to which the eggs become attached and are carried like a bunch of grapes. This paper examines the anatomy and histology of the hook. The osteological basis of the hook is shown to be a modification of the supraoccipital crest of the skull covered by typical teleost skin. The integument in the cleft of the hook, where the eggs are attached, is considerably different from ordinary fish skin. The stratified epidermis is devoid of secretory mucus and neurosensory cells and is folded into crypts that extend deeply into the dermis. This may be a specialization that facilitates adhesion of the sticky egg mass. Field observations show that this cleft area of the hook is edematous, and histology confirms that the area is highly vascularized. We speculate that this may facilitate gas exchange and/or nutrition between the male and the egg mass, but this can only be confirmed by physiological experiments with pregnant males in captivity. Engorgement with blood in the highly vascularised dermis of the hook may help hold the egg mass in place.     

Male and female contributions to heterosis in lifetime performance of mice

Summary Six straightbred lines of mice, some of their F₁ crosses and a synthetic line were used to evaluate male and female contributions to heterosis in lifetime performance measured on females. Females from each straightbred line or F₁ crosses were pair-mated randomly at day 42 with either a male of the corresponding genetic group or from a synthetic line, and pairs were maintained for 155 days (lifetime). Each mother was allowed to rear all young born alive until day 18 when the young were discarded. Data were analyzed using a model in which the group mean of lifetime performance was expressed as the sum of (additive direct) genetic and environmental effects for each of the male and female genetic groups used for mating. Comparison of group means for lifetime performance revealed that estimates of F₁ heterosis due to male and female averaged 10 and 9% for number of parturitions during lifetime, 7 and 28% for total number of young born alive, 6 and 31% for total body weight of young born alive, 8 and 33% for total number of young raised to day 18, 9 and 43% for total body weight of young raised to weaning, and 8 and 8% for days from first mating to last parturition. The male's contribution to heterosis in lifetime performance was smaller than female's contribution for productive traits (total number of young born alive and at day 18, and total body weight of young born alive and at day 18), and was nearly equal in reproductive traits (number of parturitions during lifetime and days from first mating to last parturition).Animal Research Centre Contribution No. 1098     

Male sexual behavior contributes to the maintenance of high LH pulsatility in anestrous female goats

The objective of this study was to determine the importance of male sexual behavior in stimulating LH secretion in anovulatory female goats. Two groups of females (n = 10 per group) were each exposed to a buck in sexual rest and submitted to natural daylength. In one group, the buck was awake, whereas in the other group, it was sedated to prevent its sexual behavior. Two other groups of goats (n = 10 per group) were exposed to sexually active bucks that had been exposed to 2.5 months of long days. In one group, the buck was awake, and in the other group, it was sedated. LH secretion was determined every 15 min from 4 h before introducing the bucks to 8 h after, then every 15 min again from 20 to 24 h after introducing the bucks. The bucks submitted to natural daylength did not stimulate LH secretion (P > 0.05), whether they were sedated or not. In contrast, both the awake and the sedated light-treated bucks induced an increase (P < 0.05) of LH pulsatility in the first 4 h following their introduction. However, pulsatility remained elevated until 24 h in the females exposed to the light-treated awake buck, whereas in the group with the light-treated sedated buck, pulsatility diminished (P < 0.05) after the first 4 h of stimulation by the buck. In conclusion, the sexual behavior of males contributes to the maintenance of a high LH pulsatility up to 24 h after introduction into a group of anovulatory goats.     

Nest defence by Magpies(Pica pica) and the brood parasitic Great Spotted Cuckoos(Clamator glandarius) in parasitized and unparasitized nests

Summary Nest defence is a frequent and widespread parental behaviour which enhances brood survival. We have found that in a Spanish Magpie population which is heavily parasitized by the brood parasitic Great Spotted Cuckoo, Magpies defend (1) unparasitized more frequently than parasitized nests, and (2) at the end of the nestling period more frequently than in other stages of the breeding cycle. Great Spotted Cuckoos are brood parasites, which means that their eggs are incubated and their nestlings are raised by members of a host species. Brood parasites are not thought to take care of their own offspring. However, we have found that Great Spotted Cuckoos sometimes scolded us on our regular visits to parasitized magpie nests (but never on those to unparasitized nests). Frequency of nest defence by cuckoos differed significantly among years, being significantly higher at the beginning of the study. Although sporadic observations of adult brood parasites feeding juveniles have been recorded, nest defence has not previously been suggested for any brood parasite.

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Nestverteidigung von durch den Häherkuckuck(Clamator glandarius) parasitierten und unparasitierten Nestern bei Elstern(Pica pica)

Zusammenfassung Nestverteidigung ist ein häufiges und weit verbreitetes elterliches Verhalten zur Erhöhung des Bruterfolges. In einer spanischen Elsterpopulation, die sehr intensiv vom Häherkuckuck parasitiert ist, wurden unparasitierte Nester häufiger verteidigt als parasitierte, und zum Ende der Nestlingsperiode wurden Nestern häufiger verteidigt als zu früheren Phasen des Brutzyklus. Häherkuckucke sind Brutparasiten, deren Eier von den Wirtseltern bebrütet und die Nestlinge von ihnen aufgezogen werden. Solche Brutparasiten kümmern sich im allgemeinen nicht selbst um ihre Nachkommen. Manchmal jedoch haßten Häherkuckuck auf uns, wenn wir parasitierte Nester der Elster kontrollierten, während an unparasitierten Nestern ein solches Hassen niemals erfolgte. Die Häufigkeit dieser Nestverteidugung der Kuckucke variierte zwischen Jahren und war signifikant häufiger zu Beginn unserer Untersuchung. Zwar wurde gelegentlich schon Füttern der Jungvögel durch elterliche Brutparasiten beobachtet, die hier festgestellte Nestverteidung ist bisher aber von keinem Brutparasiten beschrieben.

     

Cooperation during prey digestion between workers and larvae in the ant, Pheidole spadonia

Digestion and distribution of nutrients are central to the growth and reproduction of social insect colonies, just as they are to individual organisms. In the case of eusocial insect species, different components of food handling and processing can be distributed among castes. This paper reports on an ant species, Pheidole spadonia, in which the adult workers butcher prey and 4^th instar larvae dissolve prey for distribution among other colony members including workers, larvae and queens. To characterize the process, six groups, each composed of twenty-five workers and thirty larvae, were provisioned with a fruit fly carcass, and then video-taped continuously for 24 hours. On average, five adult workers and twenty-two 4^th instar larvae invested 12.8 labor hours into butchering and predigesting one fly carcass. Workers contributed a mean total of 3.3 labor hours to butcher the carcass into small fragments. Fourth instar larvae contributed a mean total of 9.5 labor hours to pre-orally dissolve the solid fragments. Surprisingly, larvae did not ingest during the dissolving process. Instead, workers ingested the dissolved prey tissue into their crops and then regurgitated it to colony members, larvae and workers, that solicited for feedings. The cooperative interactions reported here between workers and larvae extend the mechanistic and evolutionary explanations for eusociality. Received 13 January 2005; revised 22 April 2005; accepted 25 April 2005.     

The cost of polygyny and the evolution of female care in poison frogs

Previous research on a variety of organisms indicates that polygyny can impose a cost on the reproductive success of females. Some authors have hypothesized that this cost may have caused the evolution of female parental care from paternal or biparental care in some lineages, particularly in poison frogs of the genus Dendrobates. In this paper, we evaluate the assumptions and theoretical implications of this hypothesis and present several game-theoretic models that clarify some of the issues. We conclude that a cost of polygyny is unlikely to drive a female care strategy to fixation on its own; however, if caring males suffer a cost of lost mating opportunities then a cost of polygyny may destabilize male care and result in the evolution of uniparental female care. A cost of polygyny on its own may be able to drive a transition from male care to biparental care. We also discuss other factors that may have influenced the evolution of parental care in the poison frogs, including results from recent field and laboratory research, and we evaluate the possibility that female care evolved from biparental, as opposed to male care.     

Maternal and paternal care in the rock cavy,Kerodon rupestris,a South American hystricomorph rodent

The maternal and paternal behavior of Kerodon rupestris was examined. Quantitative differences between fathers and mothers and between mothers raising young with fathers present and with fathers absent were assessed. Growth rates of young raised by paired females and by lone females were compared. The male provides direct paternal care to the young by engaging in allogrooming, sniffing, and huddling. There is no significant difference between the sexes in the amount of contact promoting behavior given to the offspring, nor are the sexes significantly different in the amount of exploratory sniffing of the offspring. When the male is absent, the female spends a greater amount of time in contact with the young. Young raised by lone females gained significantly more weight than young raised by paired females. The suggestion that indirect paternal care acts to reduce female aggression to the young and relieve the energy expenditure burden of the female is discussed. The results indicate that social experience is gained at the expense of physical nurturing when the male is present.     

杂色山雀双亲差异性育雏策略

社会性单配制鸟类的配偶双方在抚育子代时常存在性别差异,不同鸟种的雌雄双亲往往采取不同的育雏策略。以杂色山雀(Sittiparus varius)为研究对象,2017年3—7月对繁殖巢箱进行录像监测,记录杂色山雀育雏期亲代投入情况。分析结果显示:1)双亲递食率在育雏前期(4—6日龄)无显著差异,而育雏后期(10—12日龄)雌性的递食率显著高于雄性。2)雌性亲鸟后期递食率较育雏前期显著增加;而雄性亲鸟育雏前期和后期递食率无显著差异。3)雌性递食率与自身喙宽呈极显著正相关,雄性递食率与双亲体征参数均无相关关系。总的来说,在育雏阶段,杂色山雀雌性亲鸟的递食率随着雏鸟的需求和自身身体质量发生调整,雌性在育雏后期递食率显著升高,而雄性亲鸟递食率无变化,这可能与育雏期双亲投入分工不同有关。     

Relative male and female contributions to the supercooling point of their offspring in Microvelia reticulata (Heteroptera: Veliidae)

Cold hardiness is a key life history trait in temperate and polar ectothermic species, as it affects survival during overwintering, but its evolution is poorly understood. While many studies of cold hardiness in insects have shown differences between species, populations or developmental stages, data on the relative contribution of individual genotypes to cold hardiness are scarce and mainly limited to drosophilid fly species. We used a sib‐analysis (paternal half‐sib/full‐sib breeding design) to estimate the relative contributions of parental generation to the supercooling point (SCP) of the offspring of a heteropteran non‐model insect species, Microvelia reticulata (Heteroptera: Gerromorpha: Veliidae). We found that parent identity affected significantly SCP values of their offspring. Magnitudes of estimated sire and dam variance components were similar but the distributions of individual contributions to SCP differed between sires and dams, which points to sex‐specific genetic or parental effects on SCP in this species. The animal model failed to find a realistic estimate of heritability (h²) of SCP, suggesting that the underlying genetics of SCP in M. reticulata can not be characterized by purely additive effects.     

Resistance to trifluoroperazine, a calmodulin inhibitor, maps to the fabD locus in Escherichia coli

A mutant, tfpA1, resistant to the calmodulin inhibitor trifluoroperazine (TFP) at 30°C, was isolated in Escherichia coli. The mutant showed a reduced growth rate at 30°C and was temperature sensitive (ts) at 42°C for growth, forming short filaments. The mutation was mapped to the 24 min region of the chromosome and the gene was cloned by complementation of the is defect. Subsequent subcloning, complementation analysis, marker rescue mapping and sequencing, identified tfpA as fabD, encoding the 35 kDa, malonyl-coenzyme A transacylase (MCT) enzyme, required for the initial step in the elongation cycle for fatty acid biosynthesis. Resistance to TFP may result from altered permeability of the cell envelope, although the mutant remained sensitive to other calmodulin inhibitors and to other antibacterial agents. Alternatively, resistance may be more indirect, resulting from alterations in intracellular Ca⁺⁺ levels which affect the activity of the TFP target in some way.