Pre-oviposition mate-guarding and mating behaviour of Argia vivida (Odonata: Coenagrionidae)

Abstract. 1. At Halcyon Hotsprings, British Columbia, Canada, male and female Argia vivida Hagen encountered to mate in two different ways.
2. In the morning (before 12.30 hours solar time), males basked at sunspots in the forest and darted out at passing females, attempting to take them in tandem (the first method of encounter).
3. If a male was successful, the pair engaged in a 31.3±4.8 min copulation followed by an hour of tandem flight before beginning oviposition.
4. As the day progressed, unmated males moved slowly toward the water and arrived at the water at about the same time as the earliest ovipositing pairs (1131±27.5 min solar time).
5. Males retained their grasp on their mates during oviposition (contact-guarding) but since some tandems separated during oviposition, non-tandem males at the water could capture recently released, gravid females (the second method of encounter).
6. The new pairs performed a brief copulation (10.2±3.38 min) and began ovipositing immediately thereafter.
7. Some females that avoided recapture attempted to oviposit unguarded.
8. We believe the long duration of morning copulations and period of tandem constitute a male strategy, which we call 'pre-oviposition guarding', to guard females until it is warm enough at the oviposition site for the females to begin ovipositing.
9. Separation of tandems during oviposition may be initiated by either member of the pair and we suggest that one benefit to a female of leaving a guarding mate is increased efficiency of oviposition when the intensity of male harassment is low.
10. The mating system of A. vivida thus comprises a series of complementary male and female mating behaviours.     

Mating tactics and male wing dimorphism in the damselfly,Mnais pruinosa costalis selys (Odonata: Calopterygidae)

Males of the damselfly,Mnais pruinosa costalis, exhibit wing color dimorphism: one form has orange wings, and the other hyaline wings which resemble female wings. The former is usually territorial and the latter uses sneaky mate securing tactics. When orange-winged males failed to establish territory, they became floaters that day. Hyaline-winged males perched around their territories and often, formed in tandem without any apparent courtship behavior when they found females. Their copulation frequency was higher and copulation duration longer than those of territorial males. A few females oviposited without remating. Total oviposition duration of females with which a hyaline-winged male mated was more than 32 min per male on average in a day Females that copulated with hyaline-winged males often remated with orange-winged residents before oviposition. Total duration of oviposition bouts of females after mating with floaters was short (15 min), while that with territorial residents was long (66 min). As a result, total oviposition duration of females with which an orange-winged male mated was about 40 min in a day. The reproductive success of the hyaline-winged males may be similar to that of the orange-winged males.     

Age-Related Variation in Mate-Guarding Intensity in the Bluethroat (Luscinia s. svecica)

Female extra‐pair copulations (EPCs) have selected for male paternity guarding strategies in many bird species. In the bluethroat, Luscinia s. svecica, males guard their mates closely during the last 2 d before the start of egg laying, but there is great individual variation in the intensity of mate guarding. Here we show that some of this variation is related to male age. Old males guarded their mates with much lower intensity and sang more than young males, although the latter difference was not statistically significant. Controlling for male age, male and female coloration and size were not significantly related to the intensity of mate guarding. We have previously shown that young and old males had a similar paternity loss in their own broods. On the other hand, old males were far more successful than young males in achieving extra‐pair fertilizations. These patterns suggest that young and old males have different trade‐offs between preventing paternity loss in own nest and gaining paternity in others, because male skills in obtaining EPCs improve with experience and/or because of female preferences for old males as copulation partners. There were no significant relationships between paternity and male mate‐guarding behaviour during the fertile period, indicating that mate guarding is not a very effective paternity‐assurance strategy in the bluethroat.     

Mating behavior and the evolutionary significance of mate guarding in three species of crane flies (Diptera: Tipulidae)

Three species of crane flies-Dactylolabis montana, Limonia simulans,and Antocha saxicola-gather near streams to mate and oviposit. All species are polygamous and sex ratios at these sites are male-biased. After a short mating bout, males guard females by standing over them during oviposition. Sperm competition appears to be intense and to follow last-male advantage, based on the packing of sperm within the two elongate spermathecae. Males of A. saxicolasuccessfully defend against rivals over 85% of the time. In contrast, defending males of D. montanaand L. simulanslose the female over 65% of the time during interactions with rivals. Despite the high frequency of loss, defending males gain additional oviposition time by engaging rivals in combat while the female continues to oviposit. Thus, a guarding male does not have to retain the female for guarding to be adaptive. Legs and claws of all species are sexually dimorphic and play an important role in guarding and defending.     

Postcopulatory Behavior in Libellula pulchella Drury (Odonata: Libellulidae) and Female Tactics for Avoiding Male Interference with Oviposition

Postcopulatory behavior was studied in Libellula pulchella, a North American dragonfly in which ovipositing females face frequent harassment by unpaired males seeking matings. Although males performed noncontact guarding of their mates after copulation, females received minimal protection since their guarders tended to leave on extended chases of other males when harassment was intense. Ovipositions by unguarded females were even more likely to be terminated by harassment and were disrupted sooner. Female tactics to minimize interference included rapid escape flights, repeated return visits to the water within short time periods, perching when severerly harassed, and proceeding with mating when clasped. Female use of multiple oviposition sites is discussed in the context of guarding effectiveness and mate recognition by males.     

The adaptive significance of mate guarding in the soapberry bug,Jadera Haematoloma (Hemiptera: Rhopalidae)

Male soapberry bugs (Jadera haematoloma)face severe mating competition at the northern edge of their range due to male-biased adult sex ratios. Copulations lasting up to 11 days may serve a mate guarding function (encompassing four or more ovipositions), but copulation duration is highly variable, with some pairings lasting as little as 10 min. Data were gathered to describe factors that influence the reproductive costs and benefits of prolonged copulation. Estimated copulation durations (mean ± SD) were 20 ± 23 h in the lab and 50 ± 8 h in the field and were only weakly affected by sex ratio. Females mated for 5 min produced as many fertile eggs as those mated for 600 min laid; they became depleted of fertile sperm after about 25 days. In twicemated females, the first male's paternity was reduced by about 60%, and all females (N = 13) whose mates were removed experimentally mated again within an average of 6 min. The outcome of sperm competition on a perclutch basis was not highly predictable. The possibility of increased sperm displacement in longer copulations was not tested. Males often guarded females during oviposition and successfully defended them from intruding single males by recopulating. Such intrusions occurred in the majority of oviposition attempts observed in nature. Even though most females mated promiscuously, in a focal aggregation with a mean sex ratio of 2.2 ± 0.4 males/female, the interval between matings by males was commonly several days. Males appeared to respond facultatively to several aspects of the distribution and availability of females. The intensities of mating competition and sperm competition indicate that monogamous mate guarding should be favored over nonguarding in nature. Unpredicted brief. pairings may result from assessment by males of female reproductive value or of their own physical condition, or from female resistance.     

Post-copulatory mate guarding by males of the demselfly Hetaerina vulnerata Selys (Odonata: Calopterygidae)

Males of the calopterygid damselfly Hetaerina vulnerata remain with their mates after copulating with them. The species exhibits two unusual features of post-copulatory mate guarding. First, a male will often leave his territory to accompany a female in tandem on a search for oviposition sites elsewhere. Second, a male will perch near his ovipositing female even though she completely submerges when egg-laying and cannot be captured and mated by another male while she is underwater. These activities carry two potential costs: (1) a male may miss other receptive females while guarding one mate and (2) he may lose his territory to an interloper while he is absent. These costs were low, however, because territorial males secured only one mating per 3.6 days on average. Moreover, 23 times out of 26, territorial males reclaimed their plots quickly after being away for 30–60 min. The gain from postcopulatory guarding came from being present to recapture a female should she fly up from the water after rejecting an oviposition site. There was a 40% chance that a female would leave one site to search for another during an oviposition bout. If the male were not present, his mate would be captured and mated by another individual (no female ever selected an oviposition site without being carried to it by a male). Her new partner would fertilize the remaining eggs in the female's clutch (if sperm precedence occurs in this species). The total number of eggs fertilized by a male will be affected by how well he prevents any one mate from copulating again before she lays her entire clutch and the total number of receptive females he captures. The variation in the degree of mate guarding by male odonates seems to be the evolutionary outcome of differences in fitness gains derived from these two competing activities in different ecological settings.     

On the biology of the damselfly Nosoticta kalumburu Watson & Theischinger (Zygoptera: Protoneuridae)

The habitat and the territorial and reproductive behaviours of a recently named Australian protoneurid damselfly, Nososticta kulumburu Watson & Theischinger are described. Nososticta kalumburu breeds in shallow, narrow (<2 m wide) fast-flowing permanent streams in the Kimberley region of Western Australia. The presence of suitable perches (protruding rocks or overhanging vegetation) seems to be important in determining its distribution. It is a sexually dimorphic species; males have prominent dark brown spots on the wings and a blue pruinescence, which the females lack. Males are strongly territorial. Territories (radius around I m) are small in both high and low density populations and are defended vigorously against conspecific males. Male courtship behaviour towards potential mates involves a vigorous hovering flight in front of, and by the side of, the female, during which the prominent dark brown spots on all four wings are dispalyed. Mean length of copulation is 15.4 min. Two stages of copulation were recognized. It is thought that the first stage which occupies most time (94.7%) is concerned with removing sperm from previous matings in the usual zygopteran manner. Oviposition begins in tandem in the stems of aquatic macrophytes or the roots of terrestrial plants that hang into thc water. Males exhibit plasticity in post-copulatory guarding bchaviour: in pairs undisturbed during the early stages of oviposition, the male may release the female before the current bout of egg-laying has been completed and attempt to regain a territory. The penis is unusual in having a heavily armoured shaft and two pairs of cornua; it is probably used in sperm removal as well as intromission.     

Body Size and Morph as Drivers of Copulation Duration in a Male Dimorphic Damselfly

Copulation duration is often highly variable within and among species. Here, we explore the roles of body size, male morph, morph frequency, and alternative reproductive tactics to explain copulation duration in the damselfly Paraphlebia zoe. P. zoe has two male morphs (pigmented or hyaline wings) which differ in reproductive tactics (territorial or non‐territorial behaviors). We also analyze the effects of season as the frequencies of both morphs tend to vary along the reproductive season. In the first non‐experimental year, we found that the relationship between body size and copulation duration depended on the time of year. Early in the season, body size positively correlated with copulation duration, while late in the year, body size negatively correlated with copulation duration. In the second experimental year (when we reversed the frequency of male morphs in the middle of the season: making pigmented males less frequent than hyaline males), size influenced copulation duration as well as morph – body size positively correlated with copulation duration, and hyaline males mated for longer than pigmented males. Contrary to our prediction, changes to the relative abundances of morphs did not influence copulation duration. Hyaline males may be under selection for longer copulation durations to compensate for their reduced access to females, as long copulations potentially lead to more rival sperm to be removed from the female sperm storage organs and/or increased mate guarding. We do not discard, however, other explanations that drive variation in copulation duration such as cryptic female choice and/or predation.     

Why are Male Columbian Ground Squirrels Territorial?

Male territorial defence is a component of many vertebrate mating systems and is often regarded as a tactic for acquiring mates. Traditionally considered within the context of overt site‐specific defence, territoriality actually may have several components which encompass a variety of behavioural tactics (e.g. post‐copulatory mate‐guarding, defence of resources that females need, defence of area around females) that underlie a mating system. The purpose of our study was to evaluate such influences on the territorial behaviour of male Columbian ground squirrels in southwestern Alberta, Canada. Males were dominant and territorial if they defended a minimum convex polygon activity range by chasing other males more within the activity range than they were chased. Subordinate males had no territory and were chased throughout their ranges, but they competed for mates by increasing chases in their activity range when nearby females were oestrous. Dominant males exhibited conditional breeding tactics, tending to chase other dominant males from their territory when nearby females were oestrous, but travelling outside their activity ranges to chase subordinate males when females were not oestrous. Although females mated first with a dominant male on whose territory they resided (and in order from oldest to youngest if several territories overlapped), mating pairs were not exclusive, as females usually mated with additional males. Males also guarded females after copulation and defended females directly just before oestrus, rather than defending territory per se during those times. Thus, males possess a repertoire of behaviours that complement site‐specific territoriality, and territory ownership serves to facilitate a first mating with females that live on the territory.     

Avoidance of egg parasitism through submerged oviposition by tandem pairs in the water strider, Aquarius paludum insularis (Heteroptera: Gerridae)

Abstract.  1. Females of the water strider Aquarius paludum insularis (Motschulsky) (Heteroptera: Gerridae) carry males on their backs and oviposit under water after copulation. This study focuses on the benefit  A. paludum insularis receives by ovipositing in tandem.
2. Males guarded females in tandem through to the end of oviposition in 85% of copulations. Females in tandem dived deeper than single females, and the density of A. paludum insularis eggs increased with water depth. The proportion of eggs parasitized by a scelionid wasp, Tiphodytes gerriphagus Marchal (Hymenoptera: Scelionidae) decreased with increasing water depth.
3. These results suggest that during oviposition guarding by males is beneficial for females, because it enables pairs to dive and lay eggs deeper and in oviposition sites where the risk of egg parasitism is lower.     

Adaptive control of copulation duration by males under sperm competition in the mite,Macrocheles muscaedomesticae

In a manure-inhabiting predatory mite, Macrocheles muscaedomesticae (Gamasida, Macrochelidae), when the female mates with two males, the first male takes nearly perfect fertilization priority (Yasui, 1988). The present study examined whether the first-male's sperm precedence is influenced by the copula-duration of the first and second males mating with the same female, and whether males control their copulation duration by assessing the probability that the mate has been inseminated by other males. Results of the artificial interruption of copulation showed that sperm precedence value, P₂ (the proportion of the offspring fathered by the second male), was negatively correlated with the copulation duration of the first male but positively correlated with that of the second male. There was a threshold (ca. 180–300 seconds) in the first-male's copulation duration beyond which P₂ decreased drastically; when length of the first copulation exceeded this threshold, the second males did not fertilize eggs, whereas they fertilized more than half of the eggs when the first-copulation duration was shorter than the threshold. Almost all males copulated for a longer period (average 509.8 seconds) than this threshold if the copulation duration of the previous male had not exceeded the threshold, but if it was longer than the threshold, second males had shortened their copulation (67.6 seconds). These results suggest that males are able to assess the insemination status of their mates and to adjust their copulation duration depending on the probability of fertilizing eggs by their own sperm. A mechanistic explanation for sperm precedence (i.e., plug-formation within sperm receptive organ of the females) is proposed.     

Costs and benefits for water strider (Aquarius paludum) females of carrying guarding, reproductive males

We describe the mating system of Aquarius paludum insularis based on field observations and test hypotheses about the effects of body size, hunger level and post-copulatory guarding on reproductive performance. The mating sequence of this species was typical for temperate water striders, except that most oviposition was carried out by tandem pairs, most of which were submerged. Mate guarding continued until the end of oviposition, lasting up to 18.2h, which was much longer than that recorded for other species of water striders. Pair partners changed after oviposition. Extended contact guarding reduced female mobility. In the case of females that carried long-winged males, there was a significant reduction in speed and stride between tandem as opposed to single females. However, when short-winged males were carried, there was not a significant difference. Short-term foraging efficiency did not differ significantly between tandem and single females, and thus did not reflect the difference in mobility. Hunger level did not significantly affect female mating receptivity. Although the number of harassment bouts by unpaired males did not differ between single and tandem females, single females suffered significantly more harassment. Females were able to lay fertilized eggs for about 15 days after a single copulation, but they accepted long guarding and multiple mating during this period as well. The cost of resisting male mating attempts appears to be greater than the cost of carrying males.     

Why do male Callosobruchus maculatus harm their mates?

Males of the bruchid beetle Callosobruchus maculatus have spineson their intromittent organs that puncture the female reproductivetract during mating. Females kick their mates during copulation.If females are prevented from kicking the males, copulationslast longer and the injuries females sustain are more severe.We tested whether or not these injuries represent real fitnesscosts that can be mitigated by kicking and also what males gainby inflicting them. Our results show that females do indeedsuffer lowered lifetime fecundity if they are prevented fromkicking. However, we could find no evidence that males gainbenefits through harming their mates. It has been suggestedthat the way females respond to the harm may benefit the malecausing it. Injured females may be less willing to remate toavoid sustaining further injuries, or they may respond by increasingtheir rate of oviposition if they perceive the injuries as athreat to their survival. In our study, however, females thatwere prevented from kicking did not respond by delaying rematingor increasing their rate of oviposition. Furthermore, preventingfemales from kicking during their second copulation did notmake their second mates more successful in sperm competition.This suggests that the spines have evolved for other reasonsthan harming the females, such as serving as an anchor duringcopulation, and that the harm they cause is a side effect ofa male adaptation and is not itself adaptive for either sex.     

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.     

Reproductive behavior of the dragonfly,Orthetrum japonicum (Odonata: Libellulidae)

The reproductive behavior of the dragonfly,Orthetrum japonicum, is described. Behavioral processes of turnover of territorial males, simultaneous guarding of 2 females by a male, and copulation by non-territorial males are described. The males with longer hind wings won the territorial conflicts more frequently. The total duration of territorial residence of a given male was correlated with the number of his matings, but not correlated with the length of his abdomen or hind wings. The territorial site with the lower degree of vegetation cover was occupied by males more consistently. Males in more consistently occupied territorial sites did not have longer abdomen and hind wings than males in less consistently occupied sites. The territorial site where the larger number of copulations was observed was not occupied more consistently. Selection episode analysis using the method of Arnold & Wade (1984a, b) showed that direct selection on the hind wing length favored the short wing and that direct selection on the abdomen length favored the long abdomen during mating.     

Repeated copulations benefit of the female inLethocerus deyrollei vuillefroy (Heteroptera: Belostomatidae)

TheLethocerus deyrollei male copulates repeatedly with the same female before and between ovipositions. Females stopped oviposition and waited for the next copulation when males were experimentally removed. This result suggests that females need to copulate before each oviposition bout. Since eggs fail to hatch without care of males, females have to detain males until the end of sequential ovipositions. Males assure their paternity with repeated copulations, and females can thus detain males.     

Female sexual receptivity and male copula guarding during prolonged copulations in the damselflyIschnura senegalensis (Odonata:Coenagrionidae)

Laboratory experiments were conducted to clarify the relationship between female sexual receptivity and male copula guarding inI. senegalensis, a species that copulates for several hours. In insectaries, most copulations were initiated early in the morning, and terminated relatively synchronously between 11 00 and 13 00. Females refused males with wing-flutter display and oviposited alone in the afternoon regardless of copulation events of that morning. Females could sexually receive males only in the morning. Males copulated for several hours until 12 00 after which females could oviposit. To determine whether copulations that last for hours function as male copula guarding or only of sperm displacement, emerged males were kept at various densities and permitted to copulate with virgin and mated females in insectaries. Both with virgin and mated females, “social” (not solitary; 2–4 males / insectary) males initiated copulations early in the morning and always terminated at around 12 00. However, both with virgin and mated females, solitary (one male / insectary) males terminated copulations in the morning. In both cases, duration of copulations did not significantly differ for virgin females and mated females. Therefore, long (several hour) copulation is more likely to function as male copula guarding than as sperm displacement, and duration of copulations is predicted to be shortened when male density is very low.     

The adaptiveness of intense contact mate guarding by males of the emerald damselfly,Lestes sponsa (Odonata, Lestidae): The male’s perspective

We studied the mating system of the emerald damselflyLestes sponsa. All males showed intense contact mate guarding by holding the female in tendem during the entire oviposition period. Our findings support the predictions made by Alcock (1994) about the occurrence of intense mate guarding: (1) a high female receptivity after copulation, (2) a high male capacity to resist takeovers, (3) sperm precedence, (4) a high operational sex ratio, (5) a high male density, (6) high access by rivals to mated females, (7) low energy expenditure, (8) a low risk of guarding, and (9) a short interval between copula and oviposition. This indicates a positive cost-benefit balance for this behavior, at least in males. A comparison within the genusLestes suggests that the male-biased sex ratios and the ease with which mated females are detected have been strong selection pressures in the evolution of intense contact mate guarding.     

Male contesis for territories and females in the fly Dryomyza Anilis

Dryomyza anilis males defend the small carcasses on which females oviposit as well as the females themselves during copulation and oviposition. Contests over territories and females, were compared to assess the way different asymmetries affect the outcome of a struggle. In contests over females with a lot of eggs the rate of take-over was lower than in contests over immature females, but the size of the female or her size relative to the owner did not affect the outcome. In territorial disputes and territories was the size difference between the opponents. Fifty-three per cent of the contests over females and 39% of territorial struggles resulted in a take-over. In take-overs, owners were smaller than copulating males or territory owners on average. Take-overs are part of a process in which resource owners continue to change until one is strong enough to defend the resource successfully. Contests over females lasted significantly longer than those over territories, which suggests that for males females are more valuable than territories. This is to be expected as territories are of value because they ultimately increase the probability of obtaining females. A positional advantage or the higher payoff of the owner in disputes over females may be the reason for the lower rate of take-over in female defence than in territorial struggles between opponents of similar size.