Male morphology and behavior correlate with reproductive success in the American redstart (Setophaga ruticilla)

Summary In a population of American redstarts (Setophaga ruticilla), we determined whether a relationship exists between seasonal reproductive success (RS) and a variety of male and female morphological and behavioral characters including plumage and male song. Adult males differ dramatically in plumage from yearling males and also exhibit variable amounts of black on their breast (bib size). Adult males were more successful than yearlings in terms of the number of eggs laid by their females. Among adult males, those with smaller bibs (less black) had females that laid more eggs, and produced more hatchlings and more fledglings. We found no evidence to indicate that this result was a consequence of territory quality. We examined a number of features of song but none alone was a predictor of RS; however, one song feature (rare repeat song) correlated with bib size. When bib size and rare repeat song were analyzed simultaneously, both were found to relate to RS. No female features were predictors of RS, but females arriving earlier at the breeding site mated with males with smaller bibs. The evidence is consistent with the view that plumage of redstarts may be used as a basis for female choice. Offprint requests to: R.E. Lemon     

Sperm characteristics associated with different male reproductive tactics in bluegills (Lepomis macrochirus)

We examined the availability and motility of sperm from parental and sneaker male bluegills (Lepomis macrochirus), a colonially nesting sunfish (Family Centrarchidae) with male parental care and a high incidence of cuckoldry by both sneaker and satellite males. We found no differences between sneakers and parentals in length and swimming speed of sperm, or percent and duration of sperm activity. In sneaker milt, however, sperm was almost 50% more concentrated than in parental milt (16.5×10⁶ vs 11.5×10⁶ sperm/μl of milt, respectively). Despite this difference in sperm concentration, stripped ejaculates from sneakers contained almost 400 million fewer sperm (only 32% as many sperm) than those from parentals due to their much smaller stripped ejaculate volumes (only about 19% that of parentals). Thus unless sneakers can compensate by releasing more sperm or gaining closer proximity to eggs at the time of spawning, they may be at a disadvantage with respect to sperm competition. We discuss these results in relation to models for the evolution of alternative reproductive behaviours in this species and suggest that the cuckolders may be making the best of a bad situation. Received: 18 February 2000 / Revised: 23 March 2000 / Accepted: 14 September 2000     

Defensive behavior of the black widow spider Latrodectus hesperus (Araneae: Theridiidae)

Summary When threatened, the black widow spider, Latrodectus hesperus, emits an adhesive, viscous web, pulls the strand from its spinnerets with its fourth pair of legs, and spreads its appendages. This behavior positions the web over the delicate abdomen, increases the area of protection, and enables the spider to place the web onto the offender, if necessary.In laboratory interactions, the viscous web protected black widows from mice (Peromyscus spp.). Mature female spiders, which had their spinnerets blocked and hence could not discharge the viscid silk, escaped less often than did black widows that were not experimentally altered.The viscid silk is palatable to mice and it appears that the deterrent effect of the web is due solely to mechanical irritation.The defensive behavior is elicited most often from mature females, which may suffer greater predation than other age groups. Males lose the ability to produce the defensive web at maturity and may shift their energy resources totally into reproductive effort.     

Territorial behavior of the black and yellow rockfish and gopher rockfish (Scorpaenidae,Sebastes)

Tagged black-and-yellow rockfish Sebastes chrysomelas and gopher rockfish S. carnatus were observed in situ for 1 yr at 3 study sites off California, USA in order to determine the nature of their home ranges and territories. Three basic patterns of space use were identified: (1) a shelter hole located within a larger area of activity (in which the fish presumably fed, since its size increased with size of fish and decreased with prey density); (2) discontinuous home ranges, in which the shelter holes and feeding areas were separte; and (3) dispersed home ranges with little or no exclusive area. Fish in the first category were regarded as territorial, since their home ranges were defended and relatively exclusive. Because individuals did not patrol borders, however, territories often overlapped at their peripheries. In addition, some territory holders appeared to tolerate the sheltering of other fish within their territories, as long as these intruders left the territory during periods of activity. Some fish with discontinuous home ranges (commuters) may have been territorial, but others may have been forced to occupy suboptimal feeding areas. Fish in the third category (floaters) were regarded as nonterritorial; their activities were apparently limited to areas where they could escape the aggression of territory holders. The varying patterns appeared to develop through defense and accommodation during the turnover of individuals, with each fish securing shelter and feeding areas as these became available.     

Spawning patterns in the leopard grouper, <Emphasis Type="Italic">Mycteroperca rosacea</Emphasis>, in comparison with other aggregating groupers

We documented the spawning patterns of the leopard grouper, Mycteroperca rosacea, from April to June 2005 in the central Gulf of California, Mexico to draw comparisons with other aggregate-spawning groupers and provide information useful for management of their fishery. Adults formed spawning aggregations of 150 to >700 individuals at specific sites, and spawning occurred daily at these sites from late April through early June. Courtship occurred throughout the day, but spawning was restricted to the evening hours. Adults spawned in groups of 6–40 fish, and pair-spawning was not observed. The group-spawning behavior of adults and the gonosomatic indices of mature males (maximum = 7.2%) suggest that sperm competition was present. The site-specificity of leopard grouper spawning aggregations and diel spawning period were typical of most aggregating groupers, and the size and structure of these aggregations was similar to other species in the genus Mycteroperca. Leopard grouper behavior patterns were unusual in that spawning aggregations persisted for extended periods, spawning was not synchronized with the lunar cycle, and adults aggregated during non-spawning periods. The extensive duration and site-specificity of spawning aggregations and the propensity of M. rosacea to form aggregations year-round increases the vulnerability of the species to overfishing. Policies that limit harvest from these aggregations are needed to improve the management of leopard grouper fisheries in the Gulf of California.     

Sounds of two entrapped humpback whales (Megaptera novaeangliae) in Newfoundland

A wide variety of sounds were recorded from two entrapped humpback whales (Megaptera novaeangliae), a female and a male, in Newfoundland, Canada, during the summers of 1975 and 1976. The sounds included pulsed moans, moans, yups, cries, chirps and clicks. Comparisons are made between the sounds of the two whales (male and female). The most frequently produced sounds, pulsed moans and moans, are compared with similar sounds that compose part of the winter song. The sounds from the New-foundland whales were not put together into songs.     

The reproductive behavior of Anthidium manicatum (Hymenoptera: Megachilidae) and the significance of size for territorial males

Summary Males of the wool-carder bee, Anthidium manicatum, patrol clumps of garden plants. Females of this species visit these plants for pollen, nectar, and pubescence; they also mate there. Females are polyandrous, with intervals between copulations as short as 35 s. Patrolling males defend their territories (0.1–1.3 m²) against other males and against other species of flower-visiting insects. Honey bees may be rendered unable to fly by the attacks of A. manicatum.Territory owners perform exploratory flights to other males' territories, changing territories often (median ownership 4–7 days; maximum 30 days) and flying up to 450 m to establish new territories. Territorial usurpations are nearly always by larger males.Female visitation rate is significantly correlated with number of flowers on a territory. The head size of territory-owner males shows significant correlation with territorial quality (measured by number of flowers, not area) and thus with number of female visits and copulatory opportunities. Some males fail to maintain territories and instead attempt to forage and copulate in other males' territories while the owners are otherwise occupied. Nonowner males are significantly smaller than owners, forage less often and from fewer flowers, and achieve significantly fewer copulations than owners. Females, however, do not reject smaller, nonowner males at a higher rate than they do larger, owner males; their choice for male size appears to be indirect, based instead on choice of food resource.The interval between a copulation and the male's next attempt with a different female is not shorter than that involving the same female. Males do not escort just-mated females about their teritories, as observed in Anthidium maculosum. Territorial behavior in this species most likely evolved through intrasexual competition for reproductive success which led to sexual dimorphism. The defense of a resourcebased territory is the mechanism used by a male to maximize his reproductive potential.     

Experimental tests of the information-center hypothesis with black vultures (Coragypsatratus) and turkey vultures (Cathartesaura)

In field tests of the information-center hypothesis (ICH) in south Texas with black vultures (Coragyps atratus) and turkey vultures (Cathartes aura), large carcasses were provided and kept under continuous observation. The use vultures made of these bait sites and their patterns of arrival were recorded to evaluate predictions derived from the ICH. Turkey vultures discovered most bait sites (30 of 31) first, but frequently were displaced from the food by later-arriving black vultures. This competitive exclusion by black vultures limited subsequent feeding opportunities for turkey vultures sufficiently that few (27%) returned on subsequent days to bait sites they had previously visited. I found no evidence that those turkey vultures that did return to bait sites acted as leaders for groups of naive birds and led them to bait sites – knowledgeable and naive turkey vultures did not arrive at bait sites together, and groups arriving at bait sites were not larger on subsequent days than on the first days carcasses were available. In contrast, a significantly larger percentage (47%) of knowledgeable black vultures returned to bait sites they had visited on previous days, and the first groups of black vultures arriving at bait sites on subsequent days were significantly larger than the equivalent groups on first days. Nine flocks of black vultures that arrived on subsequent days at bait sites before sunrise (which suggests the birds had commuted directly from a roost) contained knowledgeable birds, and two of these flocks contained both knowledgeable and naive individuals. Overall, 10 of 54 naive tagged black vultures (18.5%) arrived at bait sites under circumstances that suggested they had followed conspecifics to the food from a roost. However, most black vultures apparently found carcasses through independent search or by using local enhancement. Therefore, I conclude that while following from roosts to food sites is a strategy used by black vultures, at this study site it is one they use relatively infrequently. Received: 20 February 1997 / Accepted after revision: 28 June 1997     

Determinants of male reproductive success in American black bears

We determined annual male reproductive success in black bears (Ursus americanus) using DNA and field data from two populations in New Mexico. We identified the likely father for 78 of 120 genotyped cubs born during 1994–2000 and calculated reproductive success for 102 males known or presumed present within designated mating regions. Age was a strong determinant of reproductive success. The observed peak in reproductive success occurred at roughly the same intermediate age (10 years) as milder peaks in body size characteristics (11–12 years) and frequency of bear-inflicted wounds (13 years), suggesting body size and fighting might be important for mating. Success was negatively associated with the distance between home range centers of males and mothers. Success of young males (<7 years old) was also negatively associated with mature male (≥7 years old) density, and increasing density shifted the peak age of reproduction higher. The dispersed distribution of females likely limited the capacity of large mature males to dominate reproduction; therefore, success was determined by a complex set of variables.     

Length polymorphism at the avpr1a locus is correlated with male reproductive behavior in a natural population of prairie voles (Microtus ochrogaster)

Laboratory studies have shown that vasopressin can influence sociosexual behavior through its action on the vasopressin 1a receptor (V1aR). There is substantial evidence that the length of a microsatellite in the gene (avpr1a) encoding for the V1aR can affect social attachment to females and paternal behavior in male prairie voles under laboratory conditions. However, previous field studies of prairie voles have failed to detect a strong effect of the length of a male’s avpr1a allele on their sociosexual behavior, but these studies are typically much shorter than the average prairie vole breeding lifespan. We examined the relationship between male avpr1a microsatellite allele length and sociosexual behavior in a natural population of prairie voles for 15 weeks, closer to the lifespan of prairie voles in nature. Contrary to predictions, we found that males with the longest avpr1a microsatellite alleles were significantly more likely to sire offspring with more than one female and to sire offspring that survived until trappable age than males with the shortest avpr1a microsatellite allele lengths. This relationship was the strongest for males with the longest tenure on the study site. As in previous field studies, we did not find evidence of a relationship between a male’s avpr1a genotype and any index of social behavior including male residency status or the number of females with which males associate. This is the first study to support the hypothesis that a male’s avpr1a genotype is a factor underlying variation in the genetic mating system of prairie voles under natural conditions.     

The ecology of Indo-Pacific grouper (Serranidae) species and the effects of a small scale no take area on grouper assemblage,abundance and size frequency distribution

This paper used the case study of the Wakatobi Marine National Park, Indonesia to examine changes in the diversity, density and maturity of grouper species over a 5-year period following the establishment of a small-scale no-take area (NTA). This work was carried out to investigate whether “small” NTAs could be effective management strategies over a time scale that is relevant to local fishery communities and their perception of management success. Our research also documents the ecology of these species, information essential if we are to understand how management practises are to affect coral reef fish species. Designation of this “small NTA” increased the density of groupers by 30% over a 5-year period of protected status. After 5 years of protection, grouper populations within this NTA were more mature and double the density of those within the adjacent lightly fished sites and nearly five times those of a heavily fished site. During this time all other nearby fished sites underwent large declines in grouper density. The nearby lightly fished Kaledupa site decreased by up to 50% year⁻¹. Such drastic declines are considered the impact of the exponential development of ever efficient and unsustainable methods of fishing within the study region. This NTA was not of benefit to all grouper species; the reasons for which are not clear. Such questions require further detailed research about the life history, population and behavioural ecology of Indo-Pacific grouper species. Such information is critical for urgently needed fisheries management. The present study found that a small scale NTA of 500 m length was large enough to increase the population of top predatory fish. In conjunction with other socially acceptable small scale NTAs it could help maintain and increase important fish stocks over a larger area. The use of “small” NTAs within networks of reserves should become a useful tool in the management of the locally exploited coral reefs.     

Spawning migration and returning behavior of white-streaked grouper Epinephelus ongus determined by acoustic telemetry

White-streaked grouper (Epinephelus ongus) is an important fishery target that forms fish spawning aggregations (FSAs) at specific spawning grounds. The aims of the present study were to investigate migration behavior and returning behavior in terms of FSA using acoustic telemetry. Among the 30 specimens tracked, three types of movement pattern were observed: type 1, high site fidelity at the release area before the spawning period, migration to the spawning ground during the spawning period and return to the release area just after the spawning period (17 specimens); type 2, high site fidelity at the release area, disappearance from the area during the spawning period but was not detected at the spawning ground and return to the release area (8 specimens); and type 3, high site fidelity at the release area was observed before, during and after the spawning period (5 specimens). For the 17 specimens that were categorized into type 1, the dates of departure from their release area and the dates of return to the release area of males were, respectively, significantly earlier and later than those of females. The duration between the departure date and the return date (“duration away”) of males was significantly longer than that of females. The duration away tended to be positively related to the condition factor. All 25 specimens that were categorized as type 1 and type 2 showed returning behaviors to the release area.     

The reproductive behavior and energetics of male gray seals (Halichoerus grypus) breeding on a land-fast ice substrate

The reproductive behavior of male gray seals (Halichoerus grypus) breeding on land-fast ice at Amet Island, Nova Scotia, was studied. Data on energy expenditure (rate of mass loss over time) were collected. The average time budget of males at Amet Island was comparable to that of land-breeding males. The behavior of males showed seasonal changes, with a decrease in the proportion of time spent in the water and an increase in agonistic behavior during the peak mating period. The estimated amount of body mass lost over the season ranged between 25.6 and 77.1 kg, and the estimated percent of initial body mass lost ranged between 7.7 and 26.5% (n=10). The maximum number of observed copulations for an individual male was nine. Only 15 out of 42 males observed during 1992 and 1993 were seen copulating. The number of observed copulations per male was strongly correlated with success in remaining close to, or attending, females (r=0.91, P<0.001, n=42). The mean duration of attendance was 4.5 ± 5.54 days (n=42). Large size was not an important factor in determining attendance success, but reproductive effort (the estimated proportion of body mass lost over the season) and success in agonistic interactions with other males were both correlated with male success.     

Assessment of microhabitat preferences in juvenile dusky grouper (Epinephelus marginatus) by visual sampling

As a top-level predator, the brown grouper Epinephelus marginatus can play an important role in maintaining the ecological balance of hard-bottom ecosystems. However, to fulfil this role, the species must have a sufficient population density and a wide size range. The presence of such a "healthy" grouper population is one of the known benefits of the protection measures applied to marine protected areas. The availability, in marine reserves, of areas suitable for settlement and recruitment of early juveniles can contribute to preserving a well-structured population. Thus, knowledge of microhabitats preferred by juvenile groupers is an important step in locating, within protected or not yet protected areas, nursery sites that might need a specific protection regime. The aim of the present work was to evaluate habitat and microhabitat preferences of juvenile E. marginatus, in comparison with two other serranids of comparable size, Serranus cabrilla and S. scriba, in the marine reserve of Ustica Island (SW Mediterranean). At different sites, located along the shallow coastal area of the reserve, 329 individuals of the three serranid species were visually surveyed by means of skin- or SCUBA-diving in June 1999. The location of each encountered fish was characterised by both biotic and abiotic variables evaluated at two spatial scales. In order to assess interspecific differences in the use of the spatial environment, the results were analysed by correspondence analysis. According to observations on a small spatial scale, juvenile groupers showed a preference for cavities and recesses, in clear contrast with both Serranus species. When out of such sheltered places, juvenile groupers avoided visually exposed locations (convex substrates and very large visual fields), preferring flat or sub-horizontal rocky substrates. Conversely, S. scriba, and especially S. cabrilla, chose rather open microhabitats (flat to convex substrates, with large to very large visual fields). On a larger spatial scale, brown groupers and the two other serranids showed no marked differences in their habitat preferences.     

Female reproductive qualities affect male painted turtle (Chrysemys picta marginata) reproductive success

Male reproductive success (RS) in polygamous species with minimal social systems is often determined by the number of mates. However, because male RS is translated through females, the number of offspring sired can also be influenced by female qualities. Empirically sufficient data to document how tradeoffs between mate number and quality influence male RS are seldom available for long-lived, iteroparous species. We combined long-term life history data (1983–2006) on the E. S. George Reserve (ESGR, MI, USA) with parentage data from 155 clutches of 59 female painted turtles (Chrysemys picta marginata) of varying reproductive frequencies (2003–2006) to determine the relative contribution of female numbers and qualities on male RS. One previously documented trait of female painted turtles that can have substantial influences on male RS is repeat paternity through the use of stored sperm to fertilize over 95 % of within-year clutches. In addition, our study found that second-clutch producing female painted turtles on the ESGR have higher among-year reproductive frequencies than do first-clutch only females. Multiple paternity was detected in 14.1 % of clutches (min-max?=?6.1–30.0 % annually), and the number of mates of both sexes was low annually (males 1.0; females 1.2) and over 4 years (males 1.1; females 1.7). Among successful males, RS varied substantially (1–32 offspring) and was strongly influenced by the combination of female reproductive frequency and repeat paternity (>38 % among years), but not mate number. Low mate number for both sexes was unexpected in a species without complex mating behaviors or parental care.     

外来入侵植物美洲商陆的繁殖生物学特性及其与入侵性的关系

美洲商陆（Phytolacca americana）是一种我国广泛分布的商陆科入侵植物。通过实验观察和人工控制套袋等方法,对其开花动态、花部综合特征、繁育系统和种子萌发率等与繁殖相关的特性进行了研究,探讨了这些繁殖特性与入侵性的关系。结果表明,美洲商陆每年6—8月开花,单花序的花期为6~7 d,单花的花期为2~4 d。其花直径、雄蕊长、花柱长、柱头直径分别为(6.43±0.15)、(2.83±0.10)、(0.92±0.06)和(1.02±0.08) mm。套袋实验表明,美洲商陆自交亲和,自交结实率较高,为(93.33±1.92)%,而其同样存在异交结实现象,开花前去雄,不套袋,自然条件下其结实率为(42.22±2.22)%,其 P/O 值为372.37±31.24,杂交指数为3。综合套袋实验、P/O 值及杂交指数,表明其繁育系统为兼性自交,有时需要传粉者。主要访花昆虫为蜜蜂科（Apidae）、胡蜂科（Vespidae）、麻蝇科（Sarcophagidae）和食蚜蝇科（Syrphidae）昆虫。种子千粒质量为6.43 g,室内萌发率相对较低,但出苗整齐,寿命长。交配机制灵活、结实量大、种子寿命长、具有克隆繁殖等特性增强了美洲商陆的入侵性,是其入侵成功的重要因素。     

Nitrogen fixation (acetylene reduction) associated with the living coral Acropora variabilis

To estimate N₂-fixation, acetylene reduction assays were carried out on portions of the branches of the coral Acropora variabilis from the west coast of Malaysia. In some experiments, a sub-surface incubation apparatus was employed that was designed to keep the coral fragments near to their natural depth of occurrence. Other shipboard experiments used metabolic inhibitors to investigate the class of organism reducing acetylene. Stumps of coral gave the highest rates of activity, probably attributable to loosely associated cyanophytes. Coral tips also reduced acetylene at relatively high rates; reduction was enhanced in light by increased CO₂ concentration and decreased O₂ tensions indicative of photosynthetic bacteria. Algal material was not obvious on the tip surfaces and so the active organism was probably more integral to the coral structure than it was in the stumps. Maximum rates of acetylene reduction measured translated to 2.5 mg N₂ fixed per outcrop per day.     

Modelling the spatial distribution of red grouper (Epinephelus morio) at Campeche Bank, México, with respect substrate

The red grouper (Epinephelus morio) has historically been one of the most important fisheries of the Campeche Bank area in the Gulf of México, where two fleets from México and one from Cuba participate. Current stocks have been estimated to be a third or less as abundant as in the 1970s; hence, the fishery has been declared to be over-exploited. The federal government of México has expressed the need to investigate the potential use of protected areas as a management tool for recovery of this species. Based on artificial neural network (ANN) modelling, we analysed the spatial distribution of red grouper with respect substrate, considering the demographic structure of the stock. We found a significant relationship between the type of substrate and the three stages of development (juveniles, pre-adults and adults). Juveniles are distributed in shallow waters close to the coast on coral substrates; pre-adults are also associated with coral substrates, but at an intermediate depth; adults are found in deeper waters on sandy substrates. We also identified seasonal reproductive aggregation patterns, always in relation to substrate types. Reproductive aggregation during the winter and early spring in the north-eastern continental shelf and the almost permanent (exception in autumn) concentration of juveniles in coastal waters around the central and eastern coast of Yucatan are of particular importance for management. These patterns represent seasons and areas of high fish vulnerability, which is the basic criterion for further analysis of protected areas.