Female and male Texas cichlids (Herichthys cyanoguttatum) do not fight by the same rules

Selection usually acts differently on males and females duringintrasexual competition for resources and/or mates. Nevertheless,agonistic behavior has been examined both theoretically andempirically mostly in males. Our research questions whethermales and females follow the same rules of engagement in intrasexualcontests as predicted by the sequential assessment model (SAM).The SAM predicts negative correlations between contest intensityand duration and the magnitude of asymmetry in resource holdingpower (RHP) between the contestants, such that the most escalatedcontests are those between similarly endowed individuals. Westaged male and female intrasexual contests with varying degreesof body size asymmetry under a round robin design using themonogamous Texas cichlid fish (Herichthys cyanoguttatum) asa study case. We used Mantel's matrix analysis to compare howthe behavioral content, duration, structure, and outcome ofmale and female contests were affected by the relative bodysize of the contestants. In the case of males, relative sizein each contest predicted outcome, duration, and frequency ofconventional and escalated behaviors according to prevailingtheory. Female contest structure and outcome, however, werenot predicted by the relative size of contestants. We discussour results in terms of other asymmetries that might be importantin structuring female contests, and we propose potential approachesto study female–female aggression.     

Diet composition of the smooth dogfish (Mustelus canis) in the waters of Long Island,New York,USA

Mustelus canis, one of two species in the genus Mustelus found along the Northwest Atlantic coast and the second most abundant shark in the region, is beginning to comprise large portions of by-catch in various commercial fishing industries. This study analysed the gut contents of sharks taken from three locations in Long Island, NY (Long Beach, Shelter Island and Gardiners Bay) to examine sex- and site-specific diet composition. Our study indicates that smooth dogfish in these waters are opportunistic predators, showing a preference for crustaceans (i.e. Cancer irroratus, Libinia spp., Squilla empusa and Upogebia affinis). Dietary niche breadth was found to vary significantly and niche overlap was moderately low between sexes and between sites. While dietary components of M. canis discovered in this study corroborate other studies performed within the Northwestern Atlantic migratory range of M. canis, smooth dogfish diet varies considerably with region and time of year. Thus, future studies should include surveys of distribution patterns for common prey items and studies of caloric components of these prey items.     

An optimum estimator of body size to relate to behavioural and physiological parameters in field studies

Body size is an essential variable in many behavioural and physiological studies. Previous methods for body size estimation present two conflicting drawbacks. They either (1) consider variation in only one dimension through linear measurements or (2) they are time and resource consuming, hard to apply in field conditions and/or stressful to the animal. We present a method for estimating body size, an ellipsoid approximation, which requires simple linear measurements and incorporates variation in three dimensions. The method is tested on two species of teleost fish and one species of insect. The amount of variance in mass explained by the proposed method exceeds that of previous reported methods, including the most accurate ones, that usually require expensive digitising procedures and/or stressful handling.     

Immediate closure of traumatic upper arm and forearm injuries with the latissimus dorsi island myocutaneous pedicle flap

This paper reports the authors' experience with latissimus dorsi island pedicle flaps in the acute treatment of massive arm injuries. Seven patients with upper arm injuries and four patients with forearm injuries were treated with latissimus dorsi pedicle flaps. All cases involved massive soft-tissue loss and open fractures. Primary healing of wounds occurred without complications in 10 of 11 patients; the eleventh developed a wound infection. There were no instances of flap loss or vascular complications. This report compares and discusses surgical management options and details the importance of robust, immediate soft-tissue coverage for optimal functional recovery. Contrary to traditional thought, delay in definitive wound closure may be unnecessary when aggressive debridement is followed by acute flap closure.     

An optimum estimator of body size to relate to behavioural and physiological parameters in field studies

Body size is an essential variable in many behavioural and physiological studies. Previous methods for body size estimation present two conflicting drawbacks. They either (1) consider variation in only one dimension through linear measurements or (2) they are time and resource consuming, hard to apply in field conditions and/or stressful to the animal. We present a method for estimating body size, an ellipsoid approximation, which requires simple linear measurements and incorporates variation in three dimensions. The method is tested on two species of teleost fish and one species of insect. The amount of variance in mass explained by the proposed method exceeds that of previous reported methods, including the most accurate ones, that usually require expensive digitising procedures and/or stressful handling.     

Mate inspection patterns in the female beaugregory damselfish (<Emphasis Type="Italic">Stegastes leucostictus</Emphasis>)

We observed female beaugregory damselfish (Stegastes leucostictus) as they interacted with males to see whether their movements fit the predictions of different mate-search models. We established high-quality and low-quality groups with low variance in breeding site quality and a medium-quality, high-variance breeding site group and compared focal observations of female nonforaging forays in each group. Only 8% of 137 forays monitored resulted in spawning events. Eighty-nine percent of the forays were less than 240 s and were within 7 m of the focal female’s territory. Average foray times and straight-line foray distances did not differ for females traveling between males in each group. Females entered high-quality breeding sites at a higher rate than low-quality sites and round-trip distances were also greatest in high-quality groups, indicating that females were following a more convoluted path. We interpret these results to mean that (a) female beaugregories separate the tasks of mate assessment and mate choice by conducting information-gathering forays between mating events, (b) forays are energetically costly and therefore usually short in duration and overall distance traveled, (c) information collection takes approximately the same time for high-quality and low-quality mates, but (d) females will alter their foray patterns in high-quality areas to collect additional information. These data are also consistent with the hypothesis that females optimize their search by employing a tiered process of assessment during information-gathering forays, first using an adjustable threshold to accept or reject each male based on his courtship and subsequently a fixed threshold to assess the quality of each breeding site.