Alternative Male Mating Tactics Research Articles

Extended Breeding Season in the Marbled Goby, Pomatoschistus Marmoratus (Teleostei: Gobiidae), in the Venetian Lagoon

Life cycle and reproductive biology of the marbled goby Pomatoschistus marmoratus was studied in the Venetian Lagoon. Lifespan was determined by reading otoliths. The maximum age recorded was 17 months juveniles occurred in samples from July to November. Nests were found in two different periods: from the middle of April to the middle of July and from the middle of August to the end of September. While individuals in a wide range of body size (35–62 mm total length) mated during the first spawning peak during the second one only small individuals (28–32 mm total length) developed during the first peak were in reproductive activity. Histological analyses showed that most of the juveniles developed during the first spawning peak delayed sexual maturation to the following year. Ripe females appeared to be multiple spawner showing an asynchronous ovary with oocytes at different stages of development. From nesting male body sizes gonadosomatic indices and histological analyses no indication of the presence of alternative male mating tactics emerged.

Reproductive apparatus and male accessory structures in two batrachoid species (Teleostei, Batrachoididae)

The morphology of the genital apparatus of two batrachoid species, Opsanus tau and Porichthys notatus, was studied. The anatomical organization of the female reproductive apparatus is similar in both species but differences are observed in the rhythm of gametogenesis with individual oocyte production asynchronous in O. tau and group synchronous in P. notatus. The male reproductive apparatus is similarly organized in the two species, with both showing enlongated testes with an efferent duct system, two main testicular ducts, a common sperm duct, and a pair of multi‐channel accessory structures. The sperm transport system consisting of the efferent duct system, main testicular ducts, and sperm duct is more developed in P. notatus and only in this species does it secrete sialoglycoproteins. Male accessory organs also secrete sialoglycoprotein in both species, but they appear more developed in O. tau. Intraspecific variability in development of accessory structures and mucin secretion was also observed between the two male morphs of P. notatus. Type I males, which build nests and perform parental care to eggs and fry, have larger accessory organs and more abundant secretion than type II males, which adopt opportunistic spawning tactics. The possible role played by mucins as components of the seminal fluid, in both species, and their inter‐and intraspecific variability are discussed in the light of the reproductive biology and the presence of alternative male mating tactics.

Mating system and alternative male mating tactics in the grass goby Zosterisessor ophiocephalus (Teleostei: Gobiidae)

Peculiar fertilization dynamics, with males releasing sperm in mucous trails lasting several hours, characterize some demersal spawning fish. The mating system was investigated in a natural population of one of these species: the grass goby Zosterisessor ophiocephalus (Pallas, 1814), a large coastal goby inhabiting seagrass meadows in shallow brackish water. Adult males ranged in size from 7.4 to 23 cm total length, but only larger ones were observed to dig and defend a burrow, where they performed parental care on eggs laid by one to several females. Field observations together with analyses of age, sperm production, trail sperm content and sperm competition tests indicated the occurrence of alternative male mating tactics, likely the expression of an ontogenetic gradient. Larger males are older than smaller ones, and while the former are territorial, the latter “sneak” territorial male spawns. The ejaculate characteristics indicate that grass goby males have functionally polymorphic spawns: in fact sperm trails of larger males last longer and release fewer sperm than those of smaller males. Sperm production over several days is more constant in larger than in smaller males, but the total number of sperm released is higher in the latter. The influence of seminal fluid in the functional intraspecific variability in sperm release in this species is discussed.

Insemination efficiency of two alternative male mating tactics in the guppyPoecilia reticulata

In this study we compared the insemination efficiency of two alternative mating tactics (courtship and sneak mating) in the guppy Poecilia reticulata by quantifying the number of sperm delivered during a copulation. During a single copulation, guppies delivered between zero and 92% of the sperm available, as determined by mechanically stripping the male's sperm reserve at rest. The absolute number of sperm delivered after courtship was three times larger than that delivered through sneak mating; nonetheless, the variance was large with both tactics and the two distributions largely overlapped. The number of sperm available at rest increased with male size. With both tactics, the number of sperm delivered was positively correlated with the sperm available. Contrary to courtship copulations, in sneak copulations there was no correlation between the number of sperm delivered and male size. However, once the data were standardized for sperm reserve, small males delivered a larger proportion of their available sperm during sneak copulation. The rate of sexual acts (sigmoid and thrust rate) before copulation was not correlated with the number of sperm available. After the occurrence of a copulation in both the courtship and sneak copulation groups, the sexual activity of the male decreased in proportion to the amount of sperm he previously inseminated.

Balancing sexual selection through opposing mate choice and male competition

Male–male competition and female mate choice act contemporaneously in the cockroach Nauphoeta cinerea and the social pheromone of males influences the outcome of both forms of sexual selection. We therefore examined the joint and separate effects of male–male competition and female mate choice to determine if the selective optima for the pheromone were the same or different. Dominant males in a newly established hierarchy mated more frequently, but not exclusively. Manipulations of the multi-component social pheromone produced by males of N. cinerea showed that both long- and close-range attraction of females by males were influenced by the quantity and composition of the pheromone. The most attractive composition, however, differed from that which was most likely to confer high status to males. Since the outcome of male–male competition can conflict with mating preferences exhibited by females, there is balancing sexual selection on the social pheromone of N. cinerea. Such balancing selection might act to maintain genetic variation in sexually selected traits. We suggest that the different forms of sexual selection conflict in N. cinerea because females prefer a blend different to that which is most effective in male–male competition in order to avoid mating with overly aggressive males.

Male dimorphism in Perdita portalis (Hymenoptera, Andrenidae) has arisen from preexisting allometric patterns

Allometric scaling coefficients were quantified using principal components analysis for eight species of closely related Perdita bees. The coefficients were mapped onto a cladogram and male dimorphism in P. portalis was found to be the derived state, whereas polymorphism was ancestral. The phylogeny explained 87.4 ± 1.1% of the variation in male head allometry among taxa, indicating that the evolution of head allometry is highly congruent with the cladogram. These results were used to place Perdita male head allometry in the context of adaptive phenotypic plasticity. Wheeler's (1991) model for the evolution of discrete alternative castes in ants is applied to the morphometric data in Perdita. We argue that the developmental rules that govern the evolution of caste polymorphism in social insects can be applied to the evolution of alternative male mating tactics in other Hymenoptera.

Sperm competition and mode of fertilization in the grass gobyZosterisessor ophiocephalus(Teleostei: Gobiidae)

Accessory structures to the male reproductive system are known in several families of teleost, but their role in sperm production patterns and fertilization dynamics is still unclear. The intraspecific variability in seminal vesicles, shown by the grass goby Zosterisessor ophiocephalus, presents an opportunity to examine both its possible correlation to alternative male mating tactics and the function of these accessory structures. In this species, males are known to release sperm in the form of sperm trails, bands of mucosubstances in which sperm are embedded. Surgical removal of seminal vesicles and histochemistry demonstrate that mucins, involved in the production of sperm trails, are secreted by the seminal vesicles. Gametes show a high longevity; sperm motility lasts on average 80 minutes. Eggs can be fertilized for several hours and do not need to be laid over trails because sperm are able to reach them via the surrounding water. Gonosomatic and seminal vesicle somatic indices, histology and histochemistry of gonads and seminal vesicles, sperm counts, and sperm trail longevity, suggest the presence of alternative male mating tactics in this species. Larger males have smaller testes and larger seminal vesicles compared to those of smaller males. The major role of seminal vesicles is mucin secretion in larger males, sperm storage in smaller ones. Trails of larger males last longer and release sperm more constantly over time than those of smaller males. Overall differences between males support the presence of differences in the intensity of sperm competition, with larger males performing nesting behaviour while smaller ones sneak spawnings. J. Exp. Zool. 283:81–90, 1999. © 1999 Wiley-Liss, Inc.

Alternative male mating tactics in a cichlid, Pelvicachromis pulcher : a comparison of reproductive effort and success

Pelvicachromis pulcher is a small African cichlid which breeds in holes. Males may either reproduce monogamously (pair males), polygynously (harem males), or be tolerated as helpers in a harem territory (satellite males). These helpers share in defence of the territory against conspecifics, heterospecific competitors and predators. There are two male colour morphs that are fixed for life and are apparently genetically deter- mined. These diAer in their potential mating strategy. Red morph males may become harem owners, while yellow morph males may become satellite males, and males of both morphs may alternatively pair up mo- nogamously. We compared the reproductive eAort and success of these three male reproductive strategies. Ef- fort was measured as attack rates, time expenditure and the risk of being injured or killed when attacking com- petitors or predators of three sympatric fish species. Reproductive success was measured by observing how many eggs were fertilized by each male when this was possible, and by using genetic markers. The number of fry surviving to independence of parental care was used as a criterion of success. The reproductive success of harem males was 3.3 times higher than that of pair males and 7 times higher than that of the average satellite male. Dominant satellite males, however, were as suc- cessful as monogamous pair males, using the measure of fertilized eggs. To our knowledge, this has not been found previously in any fish species. Both harem and pair males had lower parental defence costs per sired oAspring, however, than males using the alternative satellite tactic. Defence eAort was significantly related to the risk of injury.

Callers and satellites: chorus behaviour in anurans as a stochastic dynamic game

Males often compete for mates using alternative tactics whose relative success could be simultaneously influenced by four factors: subsequent behaviour, physiological state, the frequency of expression of alternative tactics and the density of competing males. Here the payoffs to two alternative male mating tactics (call and satellite) were examined in anurans using a stochastic dynamic game. The basic model considers an iteroparous species with a prolonged breeding season and fairly low energetic costs and predation risks. The model assumes that female chorus attendance is affected by weather, time of year and male chorusing intensity. Results show that interactions between energetic costs of calling, density-dependent predation risk and female arrival rates, and frequency-dependent mating success produce distinct temporal waves of male chorusing despite continuously favourable environmental conditions. Relative to second-year males, first-year males attended choruses less often and were more likely to become satellites. When the energetic costs of calling were increased, waves became shorter and less frequent, and some older calling males switched to satellite behaviour. Satellites were less common when breeding season length was constrained by extrinsic factors such as seasonal weather patterns. Extrinsic constraints may also affect system stability: if female arrival rates are independent of male chorusing intensity, an evolutionarily stable strategy occurs only if the breeding season is short. Even without extrinsic constraints, the breeding season may be short if predation rates on adults are sufficiently high, or if satellites intercept a large fraction of incoming females. Thus, the ‘explosive’ breeding systems observed in many anuran species could result from either biotic or abiotic causes.

Genetic polymorphism for alternative mating behaviour in lekking male ruff Philomachus pugnax

ALTERNATIVE male mating tactics are widespread among animal taxa1–3, but there are few well documented examples of genetic polymorphisms for them4–6. The dimorphism in male courtship behaviour between independent and satellite ruffs, Philomachm pugnax7,8 (a lekking sandpiper), has often been cited as a potential example but this has been questioned9,10 because of the lack of data11 and the widespread phenotypic plasticity in the development or expression of alternative tactics in other species1–3,9,12–14. By rearing ruffs in captivity, we now show that differential morph development is genetically controlled and consistent with a single-locus, two-allele autosomal genetic polymorphism. Several potentially relevant environmental factors do not appear to alter behavioural development.

Chorus organization and male mating behavior in the Japanese pond frog,Rana porosa brevipoda

Male mating behavior of a Japanese pond frog,Rana porosa brevipoda, was observed in an enclosed pond. Males organized chorus aggregation during the night. Within the chorus, most males defended “floating” territories. Territorial males exhibited 2 types of calls: advertisement and encounter. Mating occurred primarily in male territories with female initiation, while most spawning occurred outside of the territories. After spawning, males returned to their territories and resumed display behavior. The mating system of this frog is analogous to the typical lek system. Alternative male mating tactics, including satellite and ambush behavior, were also observed. Satellite and ambush males mated with females through forced clasping.

Temperature-induced alternative male mating tactics in a tropical digger wasp

Les changements de temperature sur les tactiques d'accouplement ont ete etudies sur S. heros

The Relative Importance of Intra- and Interspecific Competition in Scorpionfly Mating Systems

Little research has examined whether interspecific competition for resources may influence the evolution of resource-based social systems in animals. An experimental field study of adults of two species of co-occurring Panorpa scorpionflies determined the relative importance of intra- and interspecific interactions at food (dead arthropods) on the fecundity, weight changes, and mating system of each species. Panorpa species exhibit resource-defense polygyny that includes not only male-male competition for dead arthropods, which are offered to females in exchange for mating, but also female mate choice and condition-dependent alternative male mating tactics. The three mating tactics used by males are arthropod defense, salivary-mass defense, and forced copulation. P. latipennis and P. mirabilis were studied because their similar ecological requirements (diet, seasonal occurrence, etc.) result in a high degree of interspecific interaction in nature and because the latter species is strongly dominant over th...

Alternative male mating tactics in Bembecinus quinquespinosus (Hymenoptera: Sphecidae): correlations with size and color variation

The digger wasp Bembecinus quinquespinosus exhibits characteristics not typical of other species in the family Sphecidae: there is no sexual size dimorphism (Fig. 1) and there is a size-linked color polymorphism among males (Fig. 2). We studied a population of this species in eastern Colorado, USA to determine if the above attributes were related to the male mating strategy.

Alternative mating tactics and the law of Diminishing Returns: The Satellite Threshold Model

The mating systems of many species comprise at least 2 alternative male mating tactics — broadly termed “Dominant” and “Satellite” tactics here. But, there exists no satisfactory conceptual framework in which to explain their co-occurrence and persistence.