Male Guarding Research Articles

Comparing population level sexual selection in a species with alternative reproductive tactics

The description of a species’ mating patterns is often based on observations from a single exemplar population; however, environmental variation can lead to variation in mating patterns and to differences in the strength of sexual selection among populations. In this study, we explored how resource distribution across a species’ range affects competition and the strength of sexual selection in a northern and southern population of plainfin midshipman (Porichthys notatus), a species with 2 male reproductive tactics. Male plainfin midshipman can be guarders that compete for nest sites and court females, or sneakers that attempt to steal fertilizations from the guarder males during spawning. Males from the north population grow larger, suggesting that there might be more competition among males in the north. However, we found that the variance in body size and in nest availability were similar between populations, suggesting instead a similar degree of male-male competition. We found no significant population differences in reproductive success (north: 517 ± 50 eggs/nest ± SE; south: 412 ± 68 eggs/nest ± SE), paternity (north: 52%; south: 58% for the guarding male), or tactic frequencies (north: 88% guarders; south: 91% guarders). There was a marginally steeper Bateman gradient in the south populat ion but no difference at 8 other measures of the strength of sexual selection between the 2 populations. Thus, despite a wide geographic distance, our results show remarkable conservation of mating patterns between the north and south populations of this benthic toadfish.

Alternative Mating Tactics as Potential Prezygotic Barriers to Gene Flow Between Two Sister Species of Frugivorous Fruit Flies

Rhagoletis completa Cresson and Rhagoletis zoqui Bush, are two sister species in the suavis group that were thought to occupy non-overlapping geographical ranges. Recent discovery of a contact zone in North Eastern Mexico where natural interspecific hybrids with intermediate morphotypes can be found has led to laboratory studies in small enclosures that failed to identify the existence of reproductive barriers capable of maintaining the genetic integrity of both species. Because the experimental approach used in such studies could have interfered with natural behavior of flies, a series of additional mating compatibility tests under much less restrictive conditions were performed. Our observations, confirmed the fact that males and females of both species engage in interspecific matings. However, R. completa females were more reluctant to engage in heterospecific matings than R. zoqui females, revealing asymmetries in sexual isolation. Also, careful scrutiny of male guarding behavior and species specific partitioning of mating location unveiled subtle differences that could result in reproductive isolation if reinforced during secondary contact.

Longitudinal Predictors of Desire to Re-enlist in the Military Among Male and Female National Guard Soldiers

Given the cost and burden associated with training and recruitment of military members, identifying predictors of military retention remains an important goal. The aim of the current study was to examine predictors of male and female service members' likelihood of remaining in the National Guard following combat deployment in support of Operation Iraqi Freedom. Using a prospective, longitudinal design, this study assessed a wide range of predictors including mental health functioning, personality variables, deployment stressors, and various domains of quality of life. Results indicated perceived unit support was the strongest predictor of intention to re-enlist for both male and female participants. However, significant gender differences emerged as predeployment depression and a trend toward perceived life threat during deployment were predictors of men's intention to re-enlist, whereas the predeployment personality dimension of introversion (low positive emotionality) and postdeployment life stressors were predictors of women's intention to re-enlist. Surprisingly, no postdeployment mental health variables predicted National Guard soldiers' intention to re-enlist. Findings from this study suggest factors associated with National Guard service members' retention or attrition from the military may be amenable to intervention.

The effect of the presence of quiescent female nymphs, males and their spermatophores on spermatophore placement in two species of eriophyoid mites

Under sex dissociated sperm transfer, females seek spermatophores and pick up sperm without male assistance. In several species males adjust spermatophore deposition rate to the presence of conspecifics. It is not known, however, which factors could favor such elasticity in non-pairing males. In this paper, we compare male response towards conspecifics between the sex dissociated eriophyoid mites Aculus fockeui (Nalepa and Trouessart) and Aculops allotrichus (Nalepa). The species differ significantly in male reproductive strategies and, consequently, the intensity of male–male-competition. Aculus fockeui males deposit spematophores all over the leaves and occasionally leave single spermatophores beside quiescent female nymphs (QFNs). In contrast, A. allotrichus males guard QFNs and encircle them with spermatophores. In this study, males of both species deposited spermatophores close to and apart from the rival spermatophores. Aculops allotrichus males had similar spermatophore output whether they were kept alone or in a group of seven males. They did not change spermatophore output in the presence of five rival spermatophores, a QFN or a QFN and varying number of rivals, either. In contrast, A. fockeui males increased spermatophore output in the presence of rival spermatophores or when on the arena with a QFN the male number increased to eight males. They did not respond, however, to the presence of a QFN and one rival or a QFN alone. The possible effect of the species-specific intensity of male–male competition, population density, the availability of receptive females and the rate of spermatophore output on the flexibility of eriophyoid spermatophore deposition is discussed.

Effect of dust and automobile exhaust fumes on security guards in Bathinda City

Background: Environmental pollution is a worldwide phenomenon. Exposure to vehicle emissions increases the risk to reduced lung function and detoriating cardiovascular performance. Aims & Objective: To measure the effect of dust and automobile exhaust fumes on security guards. Material and Methods: The study was conducted in 150 healthy non-smoking male security guards of age group 20-40yrs. Peak Expiratory Flow Rate (PEFR) was measured using Wrights peak flow meter and acute changes in oxygen saturation (SPO2) were determined using Digital finger Pulse Oximeter in equal number (n=50 each) of security guards working outside office, in open parking and in basement parking. Statistical analysis was carried out by unpaired student’s t -test. Results: PEFR was found to be lower (427.0 ± 11.12 L/min) in security guards working in basement parking of shopping malls as compared to security guards working in open parking (430 ± 12.92 L/min) and outside office buildings (443 ± 13.29 L/min). Acute change in Oxygen saturation, (SPO2) were normal in each occupation but were significantly lower in security guards in basement parking p

Reproductive behavior ofAcanthagrion truncatumSelys, 1876 (Odonata: Coenagrionidae)

Behavioral data on Neotropical coenagrionids is still scanty, with very few studies on their reproductive behavior. Here we present the first description of the reproductive behavior of A. truncatum in a high density population in the Brazilian Neotropical savanna. The observations were made at a pond in an ecological reserve. Males remain at the water searching for females. Females remain in the surrounding vegetation and only approach the water to mate and oviposit. The mean duration of copulation was 25.6±3.26 minutes. Copulations are concentrated between 12:00 and 14:00 h (71%). Females oviposit in tandem with males, sometimes submerging to oviposit. Oviposition took 43.08±22.17 minutes. Female underwater oviposition seems to disrupt male guarding and females emerge from the water by themselves. Male–male interactions usually consist of chases and “facing off”. This damselfly species is apparently non-territorial, since males did not defend resources and searched for females in the area.

Assortative mating by size without a size-based preference: the female-sooner norm as a mate-guarding criterion

The study of size-assortative mating, or homogamy, is of great importance in speciation and sexual selection. However, the proximate mechanisms that lead to such patterns are poorly understood. Homogamy is often thought to come from a directional preference for larger mates. However, many constraints affect mating preferences and understanding the causes of size assortment requires a precise evaluation of the pair formation mechanism. Mate-guarding crustaceans are a model group for the study of homogamy. Males guard females until moult and reproduction. They are also unable to hold a female during their own moult and tend to pair with females closer to moulting than them. Using a theoretical approach, we tested the potential for size-assortative mating to arise from such a state-dependent male decision rule. Consistent with previous experimental observations, we found a pattern of size assortment that strengthened with male–male competition over females. This decision rule, which we call the female-sooner norm, may be a major cause of homogamy in mate-guarding crustaceans. This highlights the potential for size assortment to arise from preferences not based on body size. It emphasizes the importance of considering pair formation processes when studying the link between preference and pattern in order to avoid inferential fallacies.

Arginine vasotocin activates aggressive calls during paternal care in the Puerto Rican coquí frog, Eleutherodactylus coqui

The Puerto Rican coquí frog, Eleutherodactylus coqui, is a directly developing frog that exhibits male territoriality and paternal behaviors. Male frogs also produce advertisement and aggressive vocalizations or calls. Territorial males emit advertisement calls to delineate territories and attract mates. Paternal males guard and brood the directly developing embryos during embryogenesis and up to five days after hatching; advertisement calling is normally absent or infrequent during paternal care. Territorial and paternal males commonly produce aggressive calls during agonistic situations. The neuropeptide, arginine vasotocin (AVT), has been shown to promote calling in anurans, including E. coqui. The objective of this study was to determine if exogenous AVT promotes calling and territorial behavior in paternal males and if it promotes males to abandon their offspring. Injections (IP) of AVT were given to paternal males immediately before the scotoperiod. Frogs were monitored for at least four hours after the injection and the following morning for calling activity and abandonment of egg clutches. AVT-injected males showed a dramatic and significant increase in aggressive calls compared to control males (saline injections). Exogenous AVT did induce advertisement calling in some paternal males but did not significantly elevate paternal males to territorial status nor did it significantly induce abandonment of eggs/embryos. In conclusion, the type of vocalization that AVT activates in E. coqui depends upon the reproductive state of the male and the social environment that surrounds the male.

Sex, stress and social status: Patterns in fecal testosterone and glucocorticoid metabolites in male Ethiopian wolves

Ethiopian wolves, Canis simensis, live in large multi-male family packs, where males are philopatric and do not disperse. Within a pack, mating and breeding is largely monopolized by the dominant male and female, although extra-pack copulations are common, and subordinate males may sire pups in neighboring packs. Regardless of paternity, all males in a pack help rear the pups. We non-invasively studied patterns in fecal testosterone and glucocorticoid metabolite concentrations using radioimmunoassays of fecal samples collected from nine wild male Ethiopian wolves between August 2007 and February 2008. We tested the predictions of the Challenge Hypothesis, namely that fecal testosterone metabolite concentrations would be higher during the annual mating season, which is the portion of the reproductive cycle when mating and increased aggression typically occur, and lower when there were pups in the pack for which to care. Contrary to the predictions of the Challenge Hypothesis, we did not detect patterns in fecal testosterone metabolite concentrations associated with reproductive stage during our study period. Similarly, we found no patterns associated with reproductive stage in male fecal glucocorticoid metabolite concentrations. Dominant males had higher average fecal testosterone and glucocorticoid metabolite concentrations than did subordinates, which may be related to higher rates of aggression and mate guarding in dominant males of group-living canids, a pattern also reported in African wild dogs, Lycaon pictus.

Communication Commentary: Psychiatric Advance Directives

Communication Commentary: Psychiatric Advance Directives

Personality traits, reproductive behaviour and alternative mating tactics in male European bitterling, Rhodeus amarus

Individual differences in behavioural traits may play a role in reproductive behaviour and it is likely that different personality types have different reproductive success across specific social environments. This suggests a role for sexual selection for personality types, including a link between behavioural traits and alternative reproductive tactics. While research on morphological differences between guarders (bourgeois males defending resources) and sneakers (males parasitizing the territories of bourgeois males) is well characterized, the role of personality in the adoption of alternative mating tactics has hitherto been largely ignored. We investigated individual behavioural differences in a sneaker‐guarder mating system using size/age-matched males of a small freshwater fish, the European bitterling (Rhodeus amarus). We predicted distinct behavioural responses by guarder and sneaker males that were consistent in different contexts, indicating the existence of behavioural syndromes associated with male mating tactic. No behavioural syndromes were detected in male R. amarus, despite ability of individual male bitterling to establish dominance, boldness and investment in sperm competition being relatively repeatable across three consecutive trials. Male aggression, though not repeatable, was negatively correlated with the number of ejaculations, indicating a trade-off between aggression and sperm loading. No association between the tendency of males to guard a territory and behavioural traits was found, despite a significant association between the tendency to guard and morphological and physiological traits, with higher relative testis size and more breeding tubercles in guarder males. Our data suggest male bitterling mating tactics are largely unconstrained by innate factors and likely to be the product of prevailing environmental and social conditions.

Function of the major cheliped in male–male competition in the hermit crab Pagurus nigrofascia

Functions of the major cheliped in pagurid hermit crabs have been studied in fights for shells. The major cheliped often shows sexual size dimorphism, suggesting that sexual selection favors the development of the male major cheliped. The function of the major cheliped in male–male competition was examined in Pagurus nigrofascia collected from April to June 2009 on the intertidal rocky shore in southern Hokkaido, Japan (41°N, 140°E). Sexual size dimorphism of the major cheliped was observed, and precopulatory guarding males had larger major chelipeds than solitary ones. Guarding males used the major cheliped to deter intruders during competitive interactions. Males without a major cheliped were disadvantaged even if they were larger than opponents and had ownership. Cheliped size affected the outcomes of contests between similar sized males. This suggests that the male major cheliped in P. nigrofascia protects mates from competitors and, consequently, enhances male mating success. Sexual selection may favor the development of the major cheliped in male pagurids.

Chelipeds are the real weapon: cheliped size is a more effective determinant than body size in male–male competition for mates in a hermit crab

To understand the evolution of weapons, we must understand both their functions and relative importance compared to body size in determining fighting success. Many decapod crustaceans develop disproportionately large chelipeds for their body size and use them as a weapon in agonistic interaction. There are, however, examples where weapons are merely signals of resource holding potential (RHP) and the RHP is actually determined by body size. We investigated the function and relative efficacy of body size and major cheliped size in male–male contests for females in the hermit crab Diogenes nitidimanus. Contests over females took two forms: (1) males preemptively guarded females and opponents did not fight with the guarding male. Cheliped size contributed significantly to the settlement of these contests and probably functioned as a visual signal for the opponents. (2) Guarding males engaged in physical combat with an opponent. In these cases, both body and cheliped sizes affected contest outcomes. The effect size for cheliped size was as strong, or stronger, than that for body size. These results suggest that large chelipeds have evolved as a true weapon and are effective in escalated fights for resources. Therefore they are also efficient visual signals for settling contests with only display. Our results are a rare example that clearly demonstrate that weapons are a more important determinant of fights than body size when both body and weapon size affect resource acquisition.

Male Morphotypes and Mating Behavior of the Dancing Shrimp Rhynchocinetes brucei (Decapoda: Caridea)

In crustaceans, the presence of large males with highly developed prehensile appendages (chelipeds or gnathopods) generally is suggestive of female monopolization during her receptive period. While mate guarding is common among some malacostracan crustaceans (brachyuran crabs and some amphipod families) it is relatively rare in caridean shrimp. Here we explored sexual dimorphism and the presence of morphotypic differences among males of the dancing shrimp Rhynchocinetes brucei. We furthermore quantified the behavioral events during mating interactions to examine whether mate guarding extends over the entire period of female receptivity. Males and females had similar body sizes, but males developed increasingly larger third maxillipeds and first chelipeds during ontogeny. Large males with hyperdeveloped maxillipeds and very large chelipeds featured a high degree of broken appendages and eyes, which probably results from intrasexual agonistic interactions. About 30% of the non-competitive male-female interactions with post-ovigerous females resulted in successful matings. Males usually initiated body contact with the female shortly after the female’s parturial molt, and they frequently touched the female’s genital region with their anterior body parts. The first (and in most cases only) spermatophore transfer event occurred at variable times (0.2-7 h) after the female’s molt. Following spermatophore transfer some males guarded the female in the cage state (between their pereiopods) until the female had finished spawning and was ovigerous. Post-copulatory mate guarding could last up to 70 min, but not all males guarded the female after the copulation. We suggest that male guarding of the receptive female throughout the mating process reduces the risk of sperm competition.

Natural History and Flash Repertoire of the Synchronous FireflyPhotinus carolinus(Coleoptera: Lampyridae) in the Great Smoky Mountains National Park

The synchronous firefly Photinus carolinus (Green) of the moist cove hardwood forests of the Great Smoky Mountains National Park attracts much public attention during its spectacular month-long mating display known as The Light Show. In previous studies flash synchrony among P. carolinus males has been investigated, but little is known about its natural history and mating behavior. This study provides additional information on the habits, flash signal variation, mating strategies, predation and historical records of P. carolinus. The polyandrous females remate throughout their approximately 3-week adult lifespan, laying successive clutches of eggs. While stationary females generally respond to male courtship signals with a receptive doublet flash signal, they also produce a rhythmic flash while walking, and can revert back to the receptive state. In this protandrous species, the average number of flashes per flash train in male courtship signals increases after females have emerged. I describe pseudo-female male flashes and group chaos flashing associated with mating clusters as well as conditions causing distress flashing in both sexes. With a backdrop of changing habitat and increasing human pressure, observations taken from the past 18 years and over 1000 h spent in the field additionally describe male guarding of a female pupa, mate guarding via prolonged copulation, common predator and phorid infestation challenges for this firefly.

Effect of body size and sex ratio on male alternative mating tactics of the West Indian sweetpotato weevil, Euscepes postfasciatus

AbstractMale body size is considered to be one of the major determinants of mating success among many insect species. Because the effectiveness of the sterile insect technique (SIT) depends on the ability of released sterile males to mate with and inseminate wild females, it is indispensable to understand the effect of male body size on the mating behavior of both sexes for the progress of the SIT program. We investigated how male body size and the presence of other rival males affect the guarding and copulatory durations of the West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae). In this species, males guard females before and after copulation. By observing the mating behavior under two sex‐ratio conditions (male‐to‐female ratios of 1:1 and 2:1), we found that small males hastened to court females when rival males were present, but the females rejected these small males as mates. Therefore, we consider that female weevils adopt a counter‐adaptation for mate preference in response to this male mating strategy. Body size did not affect the durations of copulation and post‐copulatory guarding. Although we found a conditional mating strategy for body size in E. postfasciatus, it is unlikely to have a large influence on the weevil‐eradication program using SIT.

Notable Trade Book Lesson Plan

It has been 34 years since the passage of Title IX. Yet women in academia are still underpaid and underrepre-sented in the full professor ranks nationwide. Why is this still an operative convention? Identities, roles, and perceptions leave some wondering if the old male guard isn’t still guarding.

Bending the Golden Rule

It has been 34 years since the passage of Title IX. Yet women in academia are still underpaid and underrepre-sented in the full professor ranks nationwide. Why is this still an operative convention? Identities, roles, and perceptions leave some wondering if the old male guard isn’t still guarding.

Genetic Assessment of the Mating System and Patterns of Egg Cannibalism in Atka Mackerel

AbstractThe mating system and patterns of gender‐specific egg cannibalism in Atka mackerel Pleurogrammus monopterygius were examined through genetic parentage analysis of embryos in egg clutches produced in captive and wild populations. Like other hexagrammid fishes, Atka mackerel exhibit polygynandry, which is characterized by serial matings by both genders within a breeding season. Most matings in captivity were pairings of females with nest‐attendant males, although parentage analysis of clutches produced in a small tank with limited nesting substrate revealed that 31% contained contributions by non—nest‐guarding males. In contrast, all egg clutches produced in a large exhibit tank were sired by guardian males. Multiple parentage, sometimes involving both genders, was detected in 35% of egg clutches collected in the field or retrieved from the guts of adult male and female cannibals. Half‐sib and unrelated full‐sib embryos were found in several putative clutches, indicating that the reproductive output from multiple males and females may be combined sequentially and fused into a single clutch. These results suggested that nest takeovers, combined with alloparental care of existing broods, represent common reproductive tactics in males. Egg cannibalism is a significant seasonal factor in the diets of male and female Atka mackerel. Analysis of loose eggs and partial egg clutches ingested by 4 female and 15 male cannibals showed that nearly all conspecific predation represented heterocannibalism. One instance of partial filial cannibalism was documented in a male that was one of multiple sires for the clutch.

Brood predation pressure during parental care does not influence parental enzyme activities related to swimming activity in a teleost fish

Predation is considered one of the main costs to reproduction but is rarely examined from a physiological perspective. In particular, little is known about the influence of brood predation pressure on the physiology of parents engaged in care. Brood defense, even when there is no direct threat to the parent, can be costly as it requires constant vigilance and chasing predators to protect the developing brood and maintain parental investment (i.e., fitness). Our goal was to examine the influence of natural variation in nest predation pressure on the physiology of the teleost smallmouth bass Micropterus dolomieu, an animal that provides sole-paternal care for developing offspring. More specifically, we used indicators of anaerobic (lactate dehydrogenase [LDH]) and aerobic capacity (cytochrome c oxidase [CCO] and citrate synthase [CS]) in axial white muscle and pectoral red muscle to test for differences in antipredator performance of nest guarding males across six lakes with natural variation in nest predation pressure. Pectoral red muscle enzyme activities and protein concentrations were highly conserved among populations, while axial white muscle showed differences in LDH activities, CCO activities and protein concentrations. However, there was no evidence for higher metabolic capacities in fish from lakes with increased brood predation pressure. Clearly, factors other than predation pressure have a greater influence on white muscle metabolic capacities. Additional research is needed to clarify the extent to which biotic and abiotic factors influence the enzyme activity and organismal performance in wild animals, particularly at the level of the individual and population.