Male Guarding Research Articles

Mating behavior of Aegla platensis (Crustacea, Anomura, Aeglidae) under laboratory conditions

The mating behavior of several decapod crustaceans has been extensively studied; however, this aspect of anomuran biology is still poorly known in some groups. Aeglids are the only anomurans inhabiting freshwaters, and the mating behavior of the species in this family is unknown. We provide the first account of the mating behavior of an aeglid, Aegla platensis, under laboratory conditions. The precopulatory phase was characterized by male agonistic display, male approach, and courtship. Males exhibited the agonistic display toward immature and mature females, but only physiologically mature females allowed males to approach. Male approach led to display of courtship behaviors (body vibration, thrust, body lifting, and abdomen flapping). During the copulatory phase, males and females touched each other with the antennae (antennae touch), and males positioned themselves beneath the females (supine position). Although sperm transfer was not directly observed, a “white mass” was detected among oocytes in the female abdominal chamber shortly after some copulations. Finally, in the postcopulatory phase, males guard females during the process of egg attachment. Despite their morphological similarities with other anomurans, the mating behavior of aeglids seems to be unique, and the freshwater environment appears to have an important role in driving these differences.

Interspecific cross-fostering affects mate guarding behaviour in great tits (Parus major)

Mate guarding is thought to decrease the likelihood of cuckoldry and, hence, increase the fitness of guarding males. Mate guarding is costly for males and must be traded off with other fitness-enhancing behaviours. Over several years, we have cross-fostered great tits ( Parus major ) to blue tits ( Cyanistes caeruleus ) and this experimental treatment has influenced the mate and rival recognition of cross-fostered birds. Here we show that cross-fostered great tit males mate guard their females less than do control great tits, regardless of whether the cross-fostered males were mated to great tit females or cross-fostered blue tit females. Cross-fostered great tit males sang more and interacted more frequently with blue tit males than did controls. Females paired to males of the two groups did not differ in the extent to which they initiated movements away from their mates. We conclude that the altered species-assortative behaviour resulting from interspecific cross-fostering influences mate guarding in great tit males, probably by cross-fostered males increasing investment in territorial behaviour at the expense of mate guarding, and/or by cross-fostered males mate guarding less due to a reduced affinity for their female. Such trade-offs may have a general significance for mate guarding species.

Mate-guarding behavior in clam shrimp: a field approach

Precopulatory mate guarding is a complex behavior, influenced by many social and physiological factors, representing a case of intersexual conflict. Mate guarding has often been analyzed with the aid of theoretical models. In these models, it is commonly predicted that mate-guarding time is influenced by encounter rates between males and females, the contenders’ relative sizes, and the possible interaction among males (i.e., ‘‘takeovers’’: one guarding male displacing another). The factors influencing male and female guarding decisions have been measured in laboratory experiments but never under natural field conditions. In this field-based study, we observed mate-guarding couples of the clam shrimp Limnadia badia in ephemeral pools on granite rock outcrops in Western Australia. We recorded guarding duration, focusing on the factors considered important in mate-guarding models: male and female size, population density, sex ratio, operational sex ratio, and the status of female receptivity. We also estimated time budgets for males, the possibility of male takeovers, and the potential role of female resistance. We found that female receptivity stage (how close the female was to molting), small male size, and low absolute female presence are key factors in decreasing mate-guarding duration. This study adds a field dimension to manipulative laboratory projects and theoretical models of mate guarding. We were able to observe the simultaneous interactions of multiple factors in the field and to make a robust examination of the ideas of intersexual conflict during mate guarding in these crustaceans. Key words: branchiopoda, density,femaleresistance,fieldobservations,intersexualconflict,Limnadiabadia,malesize,sexratio,WesternAustralia. [BehavEcol]

Male songbirds provide indirect parental care by guarding females during incubation

Across many taxa, guarding of fertile mates is a widespread tactic that enhances paternity assurance. However, guarding of mates can also occur during the nonfertile period, and the fitness benefits of this behavior are unclear. Male songbirds, for example, sometimes guard nonfertile females during foraging recesses from incubation. We hypothesized that guarding postreproductive mates may have important, but unrecognized, benefits by enhancing female foraging efficiency, thereby increasing time spent incubating eggs. We tested the hypothesis in 2 songbird species by examining female behavior during natural and experimentally induced absences of males. Male absence caused increased vigilance in foraging females that decreased their efficiency and resulted in less time spent incubating eggs. Male guarding of nonfertile females can thus provide a previously unrecognized form of indirect parental care. Copyright 2009, Oxford University Press.

An unusual case of nasal mucormycosis caused by Rhizopus oryzae in a German shepherd dog.

Summary This study represents an unusual case of mucormycosis localized in nasal cavity of a German shepherd dog. The patient was a 1-year-old male guard dog with unilateral nasal epistaxis, mucopurulent nasal discharge, sneezing and nose pawing. The dog had a history of head trauma about 2 months before admission, which was associated with mild self-limited epistaxis. Initial nasal rhinoscopy showed severe turbinate destruction. The samples of nasal discharge were collected by nasal flush technique and submitted to the Central Laboratory of School of Veterinary Medicine in Tehran for routine cytological, mycological and bacteriological examinations. Direct microscopic examination with 10% KOH/DMSO wet mount revealed the fragments of non-septate hyphae. The fungus was recovered in culture and identified as Rhizopus oryzae. This case showed that the veterinary practitioners should be aware of the possibility of localized nasal mucormycosis when examining dogs with chronic nasal discharge.

Morphological and developmental studies on the eggs of four <I>Coryphopterus</I> species (Actinopterygii: Gobiidae) in the caribbean sea

Currently, the gobiid genus Coryphopterus Gill, 1863 includes 13 western Atlantic species (Victor 2008). The sand dwelling species have been reported to live in similar habitats and therefore the question arises in how far they differ in ecological aspects such as their reproductive biology. No information has been presented on that topic, in particular their egg morphology, mode of attachment and development of eggs. This study investigates the morphology of eggs as well as aspects of their development and compares the results within the genus and to other gobiids. Eggs of Coryphopterus venezuelae Cervigon, 1966; Coryphopterus dicrus Bohlke et Robins, 1960; Coryphopterus eidolon Bohlke et Robins, 1960; and Coryphopterus thrix Bohlke et Robins, 1960 were collected under laboratory conditions and studied under a scanning electron microscope (SEM). These species are of similar size, with a maximum length of 5–7 cm and live associated with coral reefs. Eggs are deposited under stones or rocks and guarded by the male till hatching (Thresher 1984). The eggshell is called zona radiata or chorion and has been reported to vary in thickness, surface structure, and adhesive filaments. In many cases the zona radiata can be used to identify species (Riehl 1995, Riehl and Patzner 1998, Giulianini and Ferrero 2000). Its main function is to protect the embryo from mechanical forces. Normally it measures between 5 and 15 μm in thickness, but may reach up to 100 μm in species like Agonus cataphractus (L.) (Actinopterygii: Agonidae), which deposit their eggs in tidal wave zones (Riehl 1995). Typically gobiid fishes lay their eggs in a dense patch of single layers on the underside of a solid structure e.g., stones, rocks or shells and the male guards them until they hatch (Miller 1984, Thresher 1984). A characteristic feature of gobiid eggs is the formation of a layer of filaments between the follicle granulosa and the zona radiata. These filaments are arranged around the micropylar pole to provide a mode of attachment for these demersal eggs (Miller 1984). Giulianini et al. (2001) have proved that spermatozoa can pass through ACTA ICHTHYOLOGICA ET PISCATORIA (2008) 38 (2): 97–102 DOI: 10.3750/AIP2008.38.2.03

Importance of Nest and Paternal Characteristics for Hatching Success in Fathead Minnow

We quantified the importance of nest and paternal characteristics for survival of eggs of Fathead Minnow, a multiple-batch spawner in which breeding males guard and tend nests. We stocked experimental ponds three weeks apart and then intensively monitored 150 nests. Nest predation by conspecifics accounted for most of the egg mortality, and 29% of all nests failed to produce hatchlings. Although egg survival was not affected by date of stocking or nest initiation, hatching success improved in larger and longer-lasting nests. Nests where paternal care was observed during our monitoring were larger, lasted longer, and thus were more likely to produce hatchlings than nests where care-giving was not observed. Over one-third of the male caregivers displayed agonistic behaviors toward nest intruders, and this index of aggressive defense was also associated with improved nest performance. Larger males nested earlier and were more likely to be aggressive than smaller males. Post-spawning mortality of these larger, early-nesting males may facilitate a mid-summer demographic shift among breeders over the spawning season: nests of large, aggressive males are followed by those of smaller or later-maturing fish, who are more likely to survive to spawn again the following year.

Reproductive Biology of the Northern Madtom, Noturus stigmosus (Siluriformes: Ictaluridae) from the Licking River, Kentucky

Abstract The reproductive biology of the northern madtom, Noturus stigmosus Taylor, was examined in the Licking River, Bath and Rowan counties, Kentucky from 2001–2006. Gonadosomatic indices suggest a discrete spawning event in mid-summer, with sexual maturity reached at approximately 60 mm standard length (SL). Clutch size was estimated at 70–110 eggs per female based on examination of mature ovaries. Males and females come into reproductive condition in early summer and exhibit secondary sexual dimorphism typical of madtoms. Four nests were discovered in early to mid-July in water 23–25°C. All nests were in cavities under large slabrocks in a raceway with moderate current (0.36–0.69 m sec−2) above a large riffle. Nests contained 40–87 eggs or embryos; no guardian males were found with any nest. Eggs reared in the lab at 21–22°C hatched about 13 days after fertilization, which is the longest reported for madtoms. Embryonic and larval development were similar to those of other madtoms. Hatchlings were 8.1...

Gender Differences in the Perception of Prisoner Abuse

We examined gender stereotypes and perceptions of aggression in 743 US psychology students at a northeastern university in the USA. Participants rated a vignette depicting torture of an Iraqi prisoner by an American soldier in which the gender of prisoner and guard were varied. The results showed that female participants viewed torture more negatively than male participants. Additionally, participants perceived the torture and killing of a female prisoner warranted significant compensation to her family. However, participants perceived violent acts by a male guard to be as serious as for a female guard, suggesting a shift in perceptions of gender role stereotypes. Our findings demonstrate a change in the gender role stereotyping for females in the military and suggest a number of future studies.

Behavioral and Olfactory Responses of Female Salaria pavo (Pisces: Blenniidae) to a Putative Multi-component Male Pheromone

The peacock blenny, Salaria pavo (Risso 1810), typically breeds in rocky shores of the Mediterranean and adjacent Atlantic coast. Males defend a territory around a hole or cavity wherein females deposit eggs that the male guards until hatching. A pair of exocrine glands on the anal fin (anal glands) of males produces a putative pheromone involved in attraction of reproductively competent females to the nest. We used behavioral assays to assess species-specific attraction of reproductively competent females to putative male pheromones, including the anal gland pheromone. Additionally, chromatographic fractions of anal glands and male-conditioned water were tested for olfactory potency in females by electro-olfactogram analysis (EOG). In a flow-through tank or fluviarium, reproductive females were attracted to male-conditioned water and to the anal gland macerate from conspecifics but not to those of a closely related heterospecific. In addition, attraction of reproductive females to conspecific anal gland macerate occurred only during their initial upstream movement in the fluviarium; this was an ephemeral response when compared with the response to male-conditioned water that attracted females throughout the entire period of observation (5 min). Reproductive females also were attracted during the entire period of observation to water-conditioned by conspecific males whose anal glands had been removed. However, the attraction was more variable than that to water conditioned by intact males. Moreover, females were not attracted to male (without anal glands) odor during their initial upstream movement in the fluviarium. Finally, non-reproductive females were not attracted to the conspecific anal gland macerate. The EOG responses of females to molecular weight fractions and solid-phase extraction and high-performance liquid chromatography fractions of anal gland macerates and male-conditioned water (with and without anal glands) suggest that the anal glands release hydrophilic odorants that consist mainly of molecules smaller than 500 Da. Furthermore, males released potent odorants that do not originate from the anal glands. We hypothesize that females respond to a multi-component male pheromone to find mates. The putative anal gland pheromone is possibly comprised of hydrophilic odorants, whereas the other component(s), presumably of gonadal origin, may be less water-soluble.

Seasonal progression and variability of repeat-effort line-drill performance in elite junior basketball players

To determine gender differences, positional differences, and patterns of change in the performance of the basketball line-drill test, 93 male (mean age 16.8 years, s = 1.1) and 95 female (mean age 16.5 years, s = 1.0) basketball players undertook 516 line-drill tests over a 5-year period. Log-transformed performance times were analysed using a mixed model that included quadratic within-participant fixed effects for time in the season and time in the programme. Changes and differences were standardized for interpretation of magnitudes. Mean performance times were 28.0 s (s = 1.3) for males and 30.4 s (s = 1.3) for females. The mean pattern of change in performance within a season differed substantially between the sexes and playing positions: male guards and female centres showed moderate to very large improvements mid-season of 1.1% and 3.5% respectively (90% confidence limits ±2.1% and ±3.0%), while female guards and male forwards showed large to very large decrements of −1.6% (±2.6%) and −2.4% (±2.0%). Over 3 years, males improved performance across all three playing positions by 1.4% (±1.3%) and females by 2.9% (±1.4%). Males improved performance by 0.2% (±0.5%) per year, whereas the performance of females deteriorated by 0.6% (±0.4%) per year. The differing patterns of performance change presumably reflect variations in training and competition loads, with short-term fluctuations in performance being managed to promote longer-term improvements.

Impact of Nest Substrate Limitations on Patterns of Illegitimacy in the Fathead Minnow, Pimephales promelas (Cypriniformes: Cyprinidae)

The fathead minnow (Pimephales promelas) is a nest-building North American cyprinid that spawns multiply and exhibits exclusive male parental care. Here, we examined the effects of nest substrate availability on the genetic mating system in 2 natural populations from the glacial pothole region of eastern South Dakota. The sites differed dramatically with respect to the type and density of available nest substrate. Substrate effects were examined by comparing the percentage and distribution of illegitimate offspring between the 2 sites. A total of 1338 embryos from 42 nests (21 from each site) were genotyped at 4 or 5 microsatellite loci. Bimodally distributed frequencies of illegitimate offspring occurred in the nests of guardian males from both sites and indicate the presence of nest takeovers as well as previously undocumented alternative reproductive tactics. As predicted, the rate of usurped nests, a previously documented behavior, was higher in the nest substrate-limited population; furthermore, males were significantly larger here and acquired more mates, suggesting a difference in sexual selection regime. Although these results are based on a single comparison between 2 sites, the results are intriguing and provide a foundation for future studies.

Resources: Internet Resources for the Independent Medical Evaluator – 2007

Abstract Rating patients with head trauma and multiple neurological injuries can be challenging. The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, Section 13.2, Criteria for Rating Impairment Due to Central Nervous System Disorders, outlines the process to rate impairment due to head trauma. This article summarizes the case of a 57-year-old male security guard who presents with headache, decreased sensation on the left cheek, loss of sense of smell, and problems with memory, among other symptoms. One year ago the patient was assaulted while on the job: his Glasgow Coma Score was 14; he had left periorbital ecchymosis and a 2.5 cm laceration over the left eyelid; a small right temporoparietal acute subdural hematoma; left inferior and medial orbital wall fractures; and, four hours after admission to the hospital, he experienced a generalized tonic-clonic seizure. This patient's impairment must include the following components: single seizure, orbital fracture, infraorbital neuropathy, anosmia, headache, and memory complaints. The article shows how the ratable impairments are combined using the Combining Impairment Ratings section. Because this patient has not experienced any seizures since the first occurrence, according to the AMA Guides he is not experiencing the “episodic neurological impairments” required for disability. Complex cases such as the one presented here highlight the need to use the criteria and estimates that are located in several sections of the AMA Guides.

Suits vs. Skins: Immigration and Race in Men in Black

Suits vs. Skins:Immigration and Race in Men in Black Heather J. Hicks (bio) While the political aftermath of the events of September 11, 2001, has triggered a national debate about the rights of immigrants, the U.S. Patriot Act is only the latest of a series of state and federal measures reflecting growing suspicion toward immigrants in the U.S. during the past decade. Certainly the Patriot Act has had the most sweeping impact, requiring immigrants from many countries to register with the INS and permitting arrests and detentions without warrants, filing criminal charges, or providing access to an attorney. Yet as early as 1994, Proposition 187 was passed in California, barring illegal immigrants from receiving basic social services; and in 1996, following the Oklahoma City Bombing, two federal laws were passed that facilitated deportation and expanded the latitude of law enforcement to investigate immigrants' activities in cases of suspected terrorism.1 Although these government actions reveal the anti-immigration disposition of powerful American lawmakers and their constituents, they do not tell the whole story of the place immigrants occupy in the contemporary U.S social formation. Indeed, the apparent distrust toward "aliens" that such legislation implies requires those of us who study contemporary culture to look to various cultural forms as a means of understanding more deeply the complex ways notions of ethnic and racial difference are being constructed by (and, inevitably, will construct) current events within America's borders. In his examination of the "place of the alien in science fiction" (27), Michael Beehler suggests a deep affinity between narratives concerning aliens from other worlds and those from other nations. "The story of the [End Page 109] alien," he argues, "is always the story of borders and of the institutional forces that try to neutralize and control those borders in the name of a certain political economy" (26). It is from this vantage point that I want to examine the 1997 blockbuster Men in Black, reading it not just as the story of an American agency that controls the flow of space aliens on and off planet Earth, but also as an expression of a contemporary American political economy in which the status of immigrants is ideologically linked to the management of African American racial difference. Men in Black articulates its anxiety about immigrants' effects on American society through its depiction of a fierce invading "bug" bent on destroying humankind. Yet it is equally preoccupied with a second, non-immigrant "alien"—a young black man, played by Will Smith, whose foreignness to the old white male guard at the center of the film is repeatedly underscored. While superficially celebrating immigrants' place in American culture, Men in Black offers its audience a cynical fantasy in which agents of white privilege use their control of knowledge and information to manipulate these two different sorts of "aliens" against one another in order to preserve the borders of their own hegemony. Underpinning this narrative of race and ethnicity is a second, economic one, in which immigrants misguidedly put themselves in the skin of the erstwhile working class, while African Americans bank on the empty promise that the economic prestige of whiteness has been outsourced from skin to suit. Catching the Bug Inevitably, an objection to thinking about Men in Black, a film about an undercover agency that "monitors and controls alien activity on the planet earth," in relation to such serious and urgent questions would be its manifest status as a light summer action-comedy. Film critic Peter Travers effectively articulates one representative view of the film, simultaneously applauding its outstanding craftsmanship and stating categorically that "Men in Black is not out to change your life" (128). As Travers's comment suggests, the pace and special effects-laden surface of the film might well place it in the category of the "post-classical," in which sheer spectacle prevails over coherent plot or deeper meaning. Critics such as Elsaesser and Buckland, however, have effectively challenged this reductive treatment of recent Hollywood films. Using the action film Die Hard as a case study, they argue: "even assuming there is [End Page 110] a new kind of emphasis on spectacle in contemporary Hollywood, . . . it...

Seasonal Progression and Variability of Repeat-Effort Line-Drill Performance in Elite Junior Basketball Players

PURPOSE: To determine gender differences, positional differences, and patterns of change in the performance of the basketball line-drill test for elite junior basketball players. METHODS: Male (n= 93, 16.8 ± 1.1 y, mean ± SD) and female (n=95, 16.5 ± 1.0 y) basketball players undertook 516 repeat-effort basketball line-drill tests over a 5-y period. Players completed the manually timed test on 2.8 ± 2.4 occasions over 1.0 ± 1.2 y. Performance times were log-transformed and analysed using a mixed model that included quadratic within-subject fixed effects for time in the season and time in the program. Changes and differences were standardized for interpretation of magnitudes. RESULTS: Mean line-drill run times were 28.0 ± 1.3 s for males and 30.4 ± 1.3 s for females. The mean pattern of change in performance within a season differed substantially between genders and playing positions: male guards and female centres showed moderate to very large improvements mid-season (1.1 % and 3.5% respectively; 90% confidence limits ±2.1% and ±3.0%), while female guards and male forwards showed large to very large decrements (−1.6, ±2.6%; −2.4, ±2.0% respectively). Over three years, males improved line-drill performance across all three playing positions by 1.4, ±1.3% and females by 2.9, ±1.4%. Males improve by 0.2, ±0.5%, while females decreased performance by 0.6, ±0.4% per year. For each year older at program entry, males and females were 0.4, ±0.9% and 0.9, ±0.7% faster respectively. CONCLUSIONS: The differing patterns of performance change between genders and positions within a season presumably reflect variations in training and competition loads in these basketball players. The challenge for coaches is to manage short-term fluctuations in performance within a season while promoting longer-term improvement.

Pseudocopulation and male-male conflict elicited by subadult females of the subsocial spider Anelosimus cf. studiosus (Theridiidae)

AbstractIn spider species with first male sperm priority, males guard subadult females as a tactic for improving their paternity. Preliminary observations in Anelosimus cf. studiosus, a subsocial species from Uruguay, showed that males court and guard subadult females. To elucidate the sexual tactics of this species, we placed two adult males with one adult female, and two other males with one subadult (penultimate) female under laboratory conditions (20 trials for each female status/group). Males courted both adult and subadult females, and subadult females were as receptive as adults, adopting the acceptance posture and pseudocopulating with males. Males performed conspicuous fights under both situations. Winner males copulated (or pseudocopulated), while the losers remained as satellites. Some females remated with satellite males. Subadult female behaviour simulating the adult receptive display could be a cheating tactic for retaining males and eliciting combats. Male-male fights and the guarding of subadult females suggest the occurrence of first male sperm priority, but the persistence of satellite males also suggests second males have some degree of paternity success. Competition could be caused by an asynchrony in female maturation at the beginning of the reproductive season, turning adult females in to the scarce resource.

Spawning Chronology, Nest Site Selection and Nest Success of Smallmouth Bass During Benign Streamflow Conditions

We documented the nesting chronology, nest site selection and nest success of smallmouth bass Micropterus dolomieu in an upstream (4th order) and downstream (5th order) reach of Baron Fork Creek, Oklahoma. Males started nesting in mid-Apr. when water temperatures increased to 16.9 C upstream, and in late-Apr. when temperatures increased to 16.2 C downstream. Streamflows were low (77% upstream to 82% downstream of mean Apr. streamflow, and 12 and 18% of mean Jun. streamflow; 47 and 55 y of record), and decreased throughout the spawning period. Larger males nested first upstream, as has been observed in other populations, but not downstream. Upstream, progeny in 62 of 153 nests developed to swim-up stage. Downstream, progeny in 31 of 73 nests developed to swim-up. Nesting densities upstream (147/km) and downstream (100/km) were both higher than any densities previously reported. Males selected nest sites with intermediate water depths, low water velocity and near cover, behavior that is typical of smallmouth bass. Documented nest failures resulted from human disturbance, angling, and longear sunfish predation. Logistic exposure models showed that water velocity at the nest was negatively related and length of the guarding male was positively related to nest success upstream. Male length and number of degree days were both positively related to nest success downstream. Our results, and those of other studies, suggest that biological factors account for most nest failures during benign (stable, low flow) streamflow conditions, whereas nest failures attributed to substrate mobility or nest abandonment dominate when harsh streamflow conditions (spring floods) coincide with the spawning season.

Nest guarding in a damselfish: evidence of a role for parasites

A potential effect of parasitism on male egg loss while guarding was tested using damselfish Stegastes planifrons. Despite an apparent low energetic cost of the parasite on the male condition, there was a significant positive relationship between egg loss and parasite load. These data provide the first evidence that parasites could play a role in male guarding behaviour. The effect of the parasite could have resulted in low male condition compensated by an increase in filial cannibalism or in a lesser ability to protect the nest from predators.

Delayed copulation as a means of female choice by the hermit crab Pagurus filholi

Male hermit crabs perform precopulatory mate-guarding behavior during their reproductive season. As females generally cannot reject guarding attempts by males, male guarding prevents females from inspecting and choosing other male mates. However, as guarding males are often replaced by other males through competition for females during the guarding phase, females may be able to select males by delaying their copulation. To examine the possibility of female choice by hermit crabs, we investigated whether female Pagurus filholi that were being guarded in the field were ready to copulate and spawn. We found that about 30% of females guarded in the field were ready to spawn, indicating that guarded females delayed copulation with their current male. Our results suggest that by delaying copulation females may exploit male–male competition to “choose” dominant males. However, delaying copulation reduced the spawning potential of females. Hence, there is a trade-off between waiting for the opportunity to mate with a dominant male and decreased spawning success if females exploit male–male competition.

Sex-biased costs in nest defence behaviours by lesser snow geese (Chen caerulescens): consequences of parental roles?

Nest defence behaviours, such as attacking predators and defending against predator attacks, expose birds to risk of injury and death. However, direct costs of such behaviours are poorly documented. To evaluate potential costs of nest defence behaviours in lesser snow geese (Chen caerulescens), we (1) estimated the proportion of interactions between arctic foxes (Alopex lagopus) and geese that resulted in physical contact and (2) examined how nest defence behaviours varied between male and female geese. We separated interactions into attacks initiated by foxes (attacks by foxes) and attacks initiated by geese (attacks by geese). Risks associated with attacks by geese were considerably lower than the risks associated with attacks by foxes; only 1 of 1,179 attacks by geese resulted in physical contact between foxes and geese, whereas 26 of 89 attacks by foxes involved such contact (two female geese were killed during these attacks). Attacks by geese were made almost exclusively by male geese (>97%), whereas female geese were involved in 75% of all attacks by foxes that resulted in physical contact with geese. There was, thus, a considerable difference in risks associated with male and female nest defence behaviours. We suggest that parental roles during nesting (i.e., females incubate and males guard) expose female geese to greater risk of injury and death. Male geese may, however, reduce the risk of injury or death to their mates with pre-emptive attacks on foraging foxes.