Contributions of reproductive experience to observation-maintained crop growth and incubation in male and female ring doves

Previous work has established that experienced male ring doves (Streptopelia risoria) can maintain prolactin-dependent crop growth and readiness to incubate by observing an incubating partner. We report that this is also true for female ring doves. The role of experience in this phenomenon was examined in separate experiments with males and females. Observation of an incubating mate from 3 days after completion of egg laying is sufficient to maintain crop growth and incubation in both male and female ring doves in their second, but not in their first, reproductive cycle. Male and female doves in their first cycle must incubate for a greater part of the cycle before observation of an incubating mate is an effective stimulus; there are no differences between first and second cycle doves separated by a glass plate from the mate and nest 8 days after laying. Experience obtained within the first cycle apparently ensures that previously neutral stimuli come to elicit prolactin secretion. The effectiveness of these stimuli is reinstated early in a second cycle.     

Have your cake and eat it too: male sand gobies show more parental care in the presence of female partners

Traditionally, male parental effort and mate attraction effortare expected to be in conflict as they compete for the sameresource budget. However, the quality of care provided by themale may be of a direct benefit to females and may provide animportant mate choice cue. In a laboratory experiment, we examinedhow males modified their parental behavior with respect to matingopportunity by allowing male sand gobies to mate with a singlefemale either in a big or small nest (a constraint on futuremating potential). We then exposed half of these males to thevisual stimulus from additional females and recorded male eggfanning and nest building (two components of care), courtshipbehavior, and reproductive success through out the brood cycle.We found that males fanned longer and more frequently and didmore nest construction in the presence of females and in bignests. Males guarding large nests courted females more thandid males guarding small nests. All males consumed eggs duringthe brood cycle, but complete clutch cannibalism was most frequentwhen males were guarding small nests in the absence of females.The pattern of filial cannibalism that we observed suggeststhat males prematurely terminated care when their reproductivepotential was low, that is, when there was little nest spacefor additional mating and no mates present. We found no supportfor a trade-off between mate attraction and parental care. Indeed,taken together our results suggest that males may use parentalcare as a courtship strategy and that males who invest in mateattraction also have higher parental effort.     

Is Mate Provisioning Predicted by Ornamentation? A Test with Northern Cardinals (Cardinalis cardinalis)

Male birds of many species feed their mates during courtship and incubation. The amount of food provided can be substantial and even essential for successful reproduction in some species, and can influence female nest attentiveness in many others. Additionally, mate provisioning may predict later nestling feeding rates. Females may thus benefit from being able to determine male provisioning effort. We assessed the expression of several ornaments, known to indicate condition in male northern cardinals (Cardinalis cardinalis), and compared these with mate provisioning rates, nestling feeding rates, and nest attentiveness. We found that male ornamentation may not be indicative of mate provisioning rates. Mate provisioning rate did not co‐vary with reproductive success, male feedings to nestlings, or nest attentiveness of females. However, females which were fed more often during incubation tended to provision nestlings less. Reduced female parental effort following extensive incubation feeding may be indicative of females using incubation feeding to assess future male parental effort. Male hormonal condition that favors high rates of nestling provisioning may be a proximate cause of mate provisioning during incubation, even in the absence of selection, favoring high rates of mate provisioning. Both sexes may have capitalized on this unselected behavior.     

Reproductive success in male sunbleak, a recent invasive fish species in the U.K.

The spawning behaviour of male nest guarding sunbleak Leucaspius delineatus , a recent invasive species in southern England, was studied and quantified for the first time. In the absence of physical differences between territorial and non‐territorial males ( i.e . colour, size, etc .), the reproductive behaviour of territorial males was analysed and related to reproductive success. The results showed that females preferred high‐courting and highly aggressive males. The initial cue in female mate choice, however, was based on courtship, while aggression was the decisive behavioural trait in influencing mate choice, providing a direct signal of physical condition and 'paternal competence'. Some males picked nest sites which were subsequently preferred by other males taking over the nest of a previous male ('communal nest'), with the new territorial male adopting the eggs already present at the nest. It appears that either due to female preference for nests already containing eggs or lower rates of sired egg predation by dilution among unrelated eggs, sunbleak males have adopted the mating strategy of allopaternal care.     

Mate availability affects female choice in a fish with paternal care: female counterstrategies against male filial cannibalism

Theory predicts that individuals should adopt counterstrategies against intersexual conflict with their mating partners if the counterstrategies are effective and cost-efficient. In fishes, males with parental care often cannibalize their own offspring, which reduces the female’s fitness and creates intersexual conflicts. Males of the goby Rhinogobius flumineus cannibalize more eggs in the nest when they have access to additional females prior to spawning. Thus, it is predicted that females will strategically avoid spawning with males that have high mate availability. In the present study, we experimentally tested this prediction. When sexual pairs were placed in tanks, most females (control females; 21/22) successfully spawned inside the nest. In contrast, when a gravid female (stimulus female) that was housed in a small transparent cage was shown to the experiment pairs prior to spawning, only about half of the females (experiment females; 16/29) spawned inside the nest; the remaining females released unfertilized eggs outside of the nest. Moreover, experiment females infrequently accepted and followed males into nests, and delayed spawning more often than control females. R. flumineus females prefer males that court frequently. Indeed, experiment females that infrequently received courtship tended to spawn outside of the nest. However, infrequent courtship alone could not explain outside-nest spawning, delay in spawning, or the shorter stay of females in nests. These results imply that the presence of a stimulus female dampens female spawning with males. We suggest that R. flumineus females may strategically reject or hesitate to spawn with males that have high mate availability, and that this spawning avoidance may be a counterstrategy against male filial cannibalism.     

Incubation feeding by male Scarlet Tanagers: a mate removal experiment

ABSTRACT Incubation feeding, where males feed their mates, is a common behavior in birds and may improve female condition, nest attentiveness, and nesting success. We used behavioral observations and a temporary mate removal experiment to test the female nutrition hypothesis for incubation feeding by male Scarlet Tanagers (Piranga olivacea). All males (N= 20) were observed incubation feeding and fed females both at the nest (x? 1.36 trips/h) and away from the nest (x? 20.1 trips/h). Male feeding rate off‐nest was negatively correlated with the duration of female foraging bouts and positively correlated with the total time females spent incubating per hour. Eggs were predated at seven of 19 (37%) nests, but nest survival during incubation was not related to either female incubation behavior or male feeding rate. During temporary removal experiments (N= 12), female Scarlet Tanagers remained on the nest significantly longer and did not have longer foraging bouts. An unexpected outcome of the removal experiments was a dramatic change in female vocal behavior. All 12 experimental females gave chik‐burr calls during the male‐removal experiments (x? bout length = 11.7 min), but during normal observation periods only six of 20 females at the incubation stage gave chik‐burr calls (x? bout length = 0.7 min, N= 20). Our results suggest that female tanagers likely gain nutritional benefits from incubation feeding, but male feeding may not improve immediate reproductive success. Nine of 54 (17%) nestlings in five of 17 broods (29%) were extra‐pair young (EPY), indicating that males could potentially benefit from incubation feeding via mate retention and fidelity as well as, or instead of, through immediate gains in reproductive success. Our study indicates that females benefit from incubation feeding and do not simply passively accept food from their mates, but instead may influence male feeding rates through direct (e.g., mate following and vocalizing) and indirect (the threat of mate abandonment or cuckoldry) means.     

Male and Female Soldier Beetles Relax Choice for Mate Quality Across Daily Courtship Periods

Mutual mate choice occurs when members of each sex will reject some potential mates in efforts to encounter better prospects later. The decision to reject may represent the interaction between mate preferences, mate availability, and temporal constraints. Theory predicts that mutual mate choice will favor relaxed choosiness as mate availability and time for courtship decline. We explored mutual mate choice in the soldier beetle, Chauliognathus pennsylvanicus (Cantharidae), where courtship consisted of males attempting to secure evasive females. We employed field observations, laboratory experiments, and stochastic simulations to investigate the decline in choosiness over the daily courtship period, during which individuals can mate at most once. We found that reproductive success of males and females increases with mate size and mating frequency. Females biased copulations toward larger mates by attempting to evade suitors, while males biased copulations by releasing the smaller females they capture. However, late in the day males and females may increase reproductive success by accepting rather than rejecting lower quality mates to maintain high mating rates. Stochastic simulations indicated that reproductive success, the product of mating frequency and mean mate size, was maximized in males and females by incrementally reducing mate standards across daily courtship periods. In the field, large males who rejected small females early in the daily courtship period rarely did so later. Large females used less effective evasive maneuvers later in the courtship period, resulting in copulations with progressively smaller males. These results support models of mutual mate choice that predict that individuals of high quality will maximize reproductive success by relaxing choosiness as the courtship period wanes.     

Role of vocalizations in the reproductive cycle of ring doves (Streptopelia risoria): effects of hypoglossal nerve section on the reproductive behavior and physiology of the female

The role of vocalizations in the reproductive cycle of female ring doves was investigated. Two-stage bilateral hypoglossal nerve section (HNS) was performed on adult females to alter their cooing and they were observed for courtship behavior with the same stimulus males used in preoperation behavioral tests. The HNS females showed a reduction in both the vocalization and wing flipping components of nest-coos but no changes in other female courtship behaviors. In addition, the HNS females failed to show the typical male courtship-induced follicular growth observed in sham-operated females. The behavior of stimulus males did not differ between groups and therefore could not account for the failure of follicular growth in the HNS females. These data suggest that the female's performance of nest-coos, or factors associated with it, may stimulate her own follicular growth.     

Antiphonal duetting and sex hormones in the tropical bush shrike Laniarius funebris (HARTLAUB).

We investigated changes in antiphonal duetting with phases of reproduction and circulating levels of luteinizing hormone, testosterone, and estradiol in slate-colored boubous (Laniarius funebris) breeding in aviaries. Frequency of overall male singing did not vary with reproductive phase while frequencies of female singing and female vocal responses to male song were reduced during incubation and feeding of nestlings. This resulted in significant changes in frequency of duetting. Males sang the sexual song type M1 more often during courtship and nest building than during the nestlings phase. Their territorial song types M2 and M4 did not vary with breeding phase. Females were less responsive to M1 during incubation and to M2 during the nest building and nestlings than during the courtship phase. Plasma levels of luteinizing hormone and testosterone increased in males from the prebreeding to the courtship phase. While testosterone decreased already during nest building and remained low during subsequent phases of reproduction, luteinizing hormone decreased during incubation and feeding of nestlings. Female luteinizing hormone levels were highest during nest building. Female estradiol levels decreased from nest building to incubation and increased again during subsequent nest building. Female testosterone levels were low but not basal and did not vary with phase. Neither the overall male and female singing frequencies nor the frequencies of male song types were correlated with hormonal state. However, female participation in territorial duets M4 correlated positively with their testosterone levels. It is suggested that in this monogamous, duetting species with prolonged pairbonds behavioral cues between the mates are more important than the hormonal state in control of male and female singing.     

Mate Choice and Spawning Success in the Fighting Fish Betta splendens: the Importance of Body Size, Display Behavior and Nest Size

Courtship displays should be exaggerated enough to attract mates and yet tempered so as not to deter them. We tested this hypothesis in the fighting fish Betta splendens by studying courtship displays and body size and their relationships with male parental quality and female fecundity, as well as the effects of display behavior and body size on mate choice decisions and spawning success. Because of their high degree of parental investment, males are expected to be discriminating in their choice of mates. Males who displayed more frequently built larger nests, a measure of parental quality, but larger males did not. When females were paired with males with high display rates, however, the pair had fewer eggs in their nest, even when accounting for female body mass. In a mate choice test using computer‐generated male stimuli that differed only in display behavior, females showed no preferences for displaying males vs. non‐displaying males, or for males with higher display rates vs. lower display rates. In similar tests in which the computer‐generated males differed only in size, females preferred larger males, but also preferred males that differed with respect to body size (negative assortative mating). Males preferred computer‐generated females that performed courtship displays over non‐displaying females, but showed no preferences for female body size. Neither a female's body size nor her display behavior was a significant predictor of her fecundity as estimated by the number of eggs released during spawning. Thus, our results suggest that female B. splendens must balance male parental quality (nest size) with the risk of potentially disruptive or dangerous behavior during spawning, and that females may minimize these risks through negative size‐assortative mating. Female display behavior, while unrelated to fecundity in our study, may attract males because it indicates reproductive readiness or serves a species‐recognition function.     

Hypothalamic monoamine turnover in ring doves (streptopelia risoria), courting,incubating and brooding young

1. The turnovers of hypothalamic 5-hydroxytryptamine (5HT), dopamine (DA) and noradrenaline (NE) were measured in male and female ring doves (Streptopelia risoria) at three stages of the breeding cycle: courtship, 3 days after pairing; early incubation, 1–2 days after egg laying; and brooding, 1–3 days after the squabs had hatched.2. In both sexes plasma LH decreased progressively from courtship through incubation to brooding young. Crop sacs were fully developed in doves brooding young but not at other stages of the reproductive cycle, indicating increased concentrations of plasma prolactin.3. The turnovers of 5HT and DA in both sexes were significantly higher (P<0.001) in doves brooding young than in birds incubating eggs or nest building. The turnover of DA was higher in females than in males at the onset of incubation. The turnover of NE was lower (P > 0.01) in females at the onset of incubation than during courtship or brooding.4. Increased turnover of hypothalamic DA may be more closely related to brooding behaviour than to changes in prolactin or LH secretion.5. Increased hypothalamic 5HT turnover in brooding doves appears to be more directly related to crop sac development, and by inference increased prolactin secretion, than to depressed plasma LH concentrations.     

Body Size and the Maintenance of Reproductive Isolation in Stickleback,Genus Gasterosteus

The blackspotted stickleback Gasterosteus wheatlandi and the widely studied threespine stickleback G. aculeatus are sympatric throughout the former’s range and share many aspects of life history and reproductive behaviour. These two species differ significantly in size, with G. wheatlandi of both sexes measured at approximately 60% of the standard length of their G. aculeatus counterparts. This study concentrated on G. wheatlandi courtship behaviour and investigated its role in the maintenance of reproductive isolation with G. aculeatus. Specifically, the roles that (1) female body size plays in influencing male courtship preferences and (2) male body size and behaviour play in female courtship preferences were investigated through dummy and live conspecific and heterospecific stimulus presentations. Male G. wheatlandi courtship preferences are consistent with previously described patterns for G. aculeatus. Males of both species preferentially approach and court the larger of two simultaneously presented live or dummy females. Thus, the smaller G. wheatlandi males are indiscriminate with respect to assortative mate choice; not only preferring to approach and court more fecund conspecific females but, more significantly, G. aculeatus‐sized females. In contrast, females of both species demonstrate strong assortative courtship preferences. When presented with pairs of flask‐enclosed males, females of both species preferentially orient and court the conspecific male over the heterospecific. Similarly, when presented with a conspecific male and a heterospecific male presented singly, females prefer to enter the nest of the conspecific. Systematic analysis of the interactions between these pairs of fish (one male, one female) demonstrates that the breakdown of courtship in heterospecific courtship occurs late in the courtship sequence when the widely differing forms of male leading behaviour results in drastically differing female responses. I suggest that, as previously described in G. aculeatus, the supernormality effect plays a significant role in mediating adaptive mate choice behaviour in G. wheatlandi. However, the added element of a larger sympatric species introduces a possible cost in time and energy devoted to courting heterospecific, and sympatric, females that the larger G. aculeatus do not likely incur. There is substantial evidence from many sympatric G. aculeatus species pairs that there is assortative mate choice based on size and/or courtship behaviour. Courtship trials suggest a more pervasive role for females in assortative mate choice. Whether it is male body size per se, or in combination with behaviour, morphology or other cues, is unresolved in the present study.     

Male mating success in the Azorean rock-pool blenny: the effects of body size, male behaviour and nest characteristics

Larger male Azorean rock-pool blennies Parablennius sanguinolentus parvicornis received more female visits, were courted more often by females and received more spawnings. Larger males also received a higher number of male intrusions, attacked more conspecifics and defended larger territories. Larger males showed more nest cleaning behaviour and a marginally non-significant trend for higher egg fanning rate. Male courtship, male attack rate against conspecifics and parental behaviour were all correlated with the frequency of female spawnings received by each male even when controlling for male size, suggesting that these behaviour patterns influence male mating success. On the other hand, a positive partial correlation was found between female courtship and the frequency of female spawnings, controlling for the number of female visits, which suggests a role for female mate choice on male mating success. Finally, males nesting in chambers in the bottom of pools received more spawnings than males nesting either in crevices or under boulders. However, nest opening area was associated significantly negatively with male mating success, when controlling for male size. Thus, the present data suggest strongly that male characteristics overrule nest characteristics in determining male mating success in the Azorean rock-pool blenny.     

Multiple Mating Increases Fecundity, Fertility and Relative Clutch Mass in the Female Leopard Gecko (Eublepharis macularius)

Females across many taxa may mate with several males or mate more than once with the same male within one reproductive event. Although many researchers have discussed the effects of multiple mating on reproductive success of females, few studies have attempted to disentangle whether the reproductive success of females differs with respect to whether females mate with multiple males or mate more than once with one male. In this study, we hypothesized that female leopard geckos (Eublepharis macularius) increase aspects of their reproductive success, such as fecundity, fertility and relative clutch mass, by mating more than once within one reproductive event, either by mating repeatedly with the same male or multiply mating with different males. We controlled for the potentially confounding variables of mating frequency and mate number by allowing females to mate once with one male, twice with the same male, or twice with two different males. We found that females that mated with more than one male laid more clutches, exhibited increased egg fertility and invested more in clutches relative to females that mated only once with one male, whereas females that mated twice to the same male were intermediate for these variables. Thus, reproductive success is higher among female leopard geckos that mated with more than one male compared to female leopard geckos that mated only once.     

Female presence affects male behavior and testosterone levels in the European starling (Sturnus vulgaris)

In this study, we confronted individually housed male European starlings (Sturnus vulgaris) with a female conspecific for 60 min to study the consequences on behavior and plasma testosterone (T) concentrations. Control males experienced a similar procedure, the only difference being that they were tested in the absence of a female. Female presence significantly affected both behavior and plasma T levels of male starlings. Experimental males spent significantly more time singing in the nest box and flew significantly more into the nest box with green nesting material during female presentations than during control periods. Control males never showed these mate attraction behaviors. In total 5 of the 16 experimental males did not respond behaviorally to the female stimulus bird (NR males). In contrast to T levels of control males, plasma T concentrations of both experimental males that did respond to the female (R males) and of NR males (which only perceived the female stimulus) were positively influenced by female presentation. The time spent singing in the nest box by experimental males (R and NR males combined) during female presence tended to be positively correlated with changes in plasma T levels. Finally, before introduction of a female, plasma T levels of R males were significantly higher than those of NR males indicating that individually housed males respond to the presence of a female conspecific by increasing their mate attraction behaviors only when a threshold plasma T concentration has been reached.     

Courtship as an honest indicator of male parental quality in the bicolor damselfish, Stegastes partitus

Previous work on the bicolor damselfish, a species with exclusivemale parental care of eggs, suggested that female mate choicewas based on male characteristics. The aims of this study wereto determine whether females discriminate among potential mateson the basis of courtship and, if so, to determine whether courtshipserves as an indicator of male parental quality. Observationsmade over two reproductive cycles showed that courtship ratesand mating success of individual males are positively correlatedand that males begin courting several days before females beginlaying eggs. Experimental manipulations showed that a male'scourtship rate is indicative of the subsequent egg survivalfrom his nest. We suggest that observed differences betweenmales in their courtship rates and parental ability may be aresult of differences in their energy reserves. These resultsdemonstrate the operation of honest advertising and lend supportto adaptive models of sexual selection. [Behav Ecol 1991;2:295–300]     

Sand goby (Pomatoschistus minutus) males exposed to an endocrine disrupting chemical fail in nest and mate competition

Endocrine disrupting chemicals (EDCs) are a widely studied group of chemicals that interfere with the endocrinology of organisms. So far, few studies have demonstrated the effect of EDCs on the reproductive behavior of aquatic wildlife. Here we show that sand goby males' (Pomatoschistus minutus) success in mating competition greatly decreases after an exposure for 7 to 24 days to 17α-ethinyl estradiol (EE2, measured concentration 4 ng L^− 1). The sand goby exhibits a polygynous mating system with male parental care, in which males compete for nest sites and females. The aim of this study was to test how EE2 exposure affects the ability of males to compete for breeding resources, i.e. nest sites and mates. First, EE2 exposed males competed over a nest site against a non-exposed, control male of the same size. Secondly, we examined male courtship behavior and female mate preferences for EE2 exposed males and similar-sized non-exposed, control males. In addition to the behavioral experiments we determined the zona radiata protein (Zrp) mRNA gene expression and measured morphometric indicators of sexual maturation. Our study revealed that EE2 treated males were not able to acquire or defend a nest site. Additionally, EE2 treated males spent significantly less time in active courtship and nest leading behavior than control males. As a result, females clearly preferred to mate with control males. However, we found no significant differences in Zrp mRNA expression or the morphometric indicators between treatments. Our study illustrates that exposure to this EDC can greatly reduce the chances of an individual reproducing successfully. Moreover, it demonstrates that severe behavioral effects can be seen before any effects are detectable at the molecular or morphometric level.     

A review of the potential of surface flow constructed wetlands to enhance macroinvertebrate diversity in agricultural landscapes with particular reference to Integrated Constructed Wetlands (ICWs)

Discriminating female mate preferences enhance the variance in reproductive success among males of a population and create a potential for sexual selection, which can account for trait evolution and diversification. Fish color patterns are among the prime targets of mate choice-driven sexual selection. Populations of the cichlid Tropheus from Lake Tanganyika display remarkable geographic color pattern variation, but the role of female choice in their rapid and rich phenotypic diversification is unclear. Males and females establish a pair bond prior to spawning monogamously, but as brood care is strictly maternal, female investment in reproduction is high and the operational sex ratio is male-biased. Therefore, variance in male reproductive success can accrue if individual males succeed repeatedly in securing a mate. To test this prediction in the red colored Tropheus moorii “Chimba”, four pairs of males were presented to a series of females and female mate preferences were inferred from pairwise interactions. There was a significant difference in mating success between the males of each pair (P < 0.001 over all trials), as—with one exception—females shared preferences for the same males. Male courtship activity was strongly correlated with female choice. Our experiment suggests that female choice contributes to the variance in male reproductive success in the tested population.     

Why do Both Parents Incubate in the Kentish Plover?

Incubation by both parents is a common parental behaviour in many avian species. Biparental incubation is expected if the survival prospects of offspring are greatly raised by shared care, relative to the costs incurred by each parent. We investigated this proposition in the Kentish plover Charadrius alexandrinus, in which both parents incubate the clutch, but one parent (either the male or the female) usually deserts after hatching of the eggs. We carried out a mate‐removal and food supplementation experiment to reveal both the role of the sexes and food abundance in maintaining biparental incubation by removing either the male or the female from the nest for a short period of time. In some nests we provided supplementary food for the parent that remained at the nest to reduce the costs of incubation, whereas other nests were left unsupplemented. Although males spent more time on incubation after their mate had been removed, females’ incubation did not change. Notwithstanding the increased male incubation, total nest attentiveness was lower at uniparental nests than at biparental controls. However, incubation behaviour was not influenced by food supplementation. We conclude that offspring desertion during incubation is apparently costly in the Kentish plover, and this cost cannot be ameliorated with supplementary food.     

The Haremic Mating System and Mate Choice in the Wide-Eyed Flounder, Bothus podas

The social structure and reproductive behaviour of the wide-eyed flounder, Bothus podas, was studied in the coastal waters around the Azorean Islands. Both sexes are territorial throughout the year. Adult males defend large territories, which include several smaller female territories. Intraspecific agonistic behaviour was frequent and differed between sexes: males were more aggressive towards other males, while females were only aggressive towards each other and juveniles. During the reproductive season and only at dawn, territorial males court and mate successively with females in their territories, and females seem to show mating fidelity to their dominant male. Such territoriality and mating patterns indicate a haremic social system in the wide-eyed flounder. In order to identify potential factors influencing female mate choice acting on this haremic system, we examined male mating success and some of its potential correlates. We found no evidence for female preference for any of the males' physical or territory characteristics. However, courtship effort was strongly correlated with the total number of attempted and successful spawnings, indicating that females seem to mate preferentially with males that court them more vigorously. Thus, our data suggest that courtship plays an important role in determining male mating success in the wide-eyed flounder and, that it may possibly serve as an honest indicator of male `quality' for female choice.