Mate fidelity in a polygamous shorebird,the snowy plover (Charadrius nivosus)

Social monogamy has evolved multiple times and is particularly common in birds. However, it is not well understood why some species live in long‐lasting monogamous partnerships while others change mates between breeding attempts. Here, we investigate mate fidelity in a sequential polygamous shorebird, the snowy plover (Charadrius nivosus), a species in which both males and females may have several breeding attempts within a breeding season with the same or different mates. Using 6 years of data from a well‐monitored population in Bahía de Ceuta, Mexico, we investigated predictors and fitness implications of mate fidelity both within and between years. We show that in order to maximize reproductive success within a season, individuals divorce after successful nesting and re‐mate with the same partner after nest failure. Therefore, divorced plovers, counterintuitively, achieve higher reproductive success than individuals that retain their mate. We also show that different mating decisions between sexes predict different breeding dispersal patterns. Taken together, our findings imply that divorce is an adaptive strategy to improve reproductive success in a stochastic environment. Understanding mate fidelity is important for the evolution of monogamy and polygamy, and these mating behaviors have implications for reproductive success and population productivity.     

Relationship type affects the reliability of dispersal distance estimated using pedigree inferences in partially sampled populations: A case study involving invasive American mink in Scotland

Estimating dispersal—a key parameter for population ecology and management—is notoriously difficult. The use of pedigree assignments, aided by likelihood‐based software, has become popular to estimate dispersal rate and distance. However, the partial sampling of populations may produce false assignments. Further, it is unknown how the accuracy of assignment is affected by the genealogical relationships of individuals and is reflected by software‐derived assignment probabilities. Inspired by a project managing invasive American mink (Neovison vison), we estimated individual dispersal distances using inferred pairwise relationships of culled individuals. Additionally, we simulated scenarios to investigate the accuracy of pairwise inferences. Estimates of dispersal distance varied greatly when derived from different inferred pairwise relationships, with mother–offspring relationship being the shortest (average = 21 km) and the most accurate. Pairs assigned as maternal half‐siblings were inaccurate, with 64%–97% falsely assigned, implying that estimates for these relationships in the wild population were unreliable. The false assignment rate was unrelated to the software‐derived assignment probabilities at high dispersal rates. Assignments were more accurate when the inferred parents were older and immigrants and when dispersal rates between subpopulations were low (1% and 2%). Using 30 instead of 15 loci increased pairwise reliability, but half‐sibling assignments were still inaccurate (>59% falsely assigned). The most reliable approach when using inferred pairwise relationships in polygamous species would be not to use half‐sibling relationship types. Our simulation approach provides guidance for the application of pedigree inferences under partial sampling and is applicable to other systems where pedigree assignments are used for ecological inference.     

The mating systems of three species of minute pirate bug,Orius sauteri,O. minutus,and O. strigicollis

We compared the mating systems and genital morphology of three Orius species dominant in Japan: Orius sauteri (Poppius), Orius minutus (L.), and Orius strigicollis (Poppius) (Heteroptera: Anthocoridae). In all three species, the males were polygamous and could inseminate at least three females at a rate of one female per day. Compared to the other two species, the O. minutus males had a lower rate of success in three consecutive mating orders. The mated females laid the same number of eggs irrespective of mating sequence. Orius minutus and O. strigicollis females were found to be monandrous, and they re‐mated with another male only when the 1st mating failed. In contrast, O. sauteri females were polyandrous and accepted a 2nd male even when the 1st mating was successful. Multiple mating with a single male did not increase their fecundity, and it decreased the hatching success of eggs. Mating with multiple males did not affect the fecundity or hatching success. Our scanning electron microscopy observation suggested that the genitalia of O. minutus and O. strigicollis were more similar in shape. The similarities in mating system and morphology between O. minutus and O. strigicollis support a close phylogenetic relationship.     

Singing strategies among male Black-browed Reed Warblers Acrocephalus bistrigiceps during the post-fertile period of their mates

Bird song is critical to mate attraction. Because singing involves fitness costs, males that sing vigorous and complex songs are thought to be of high quality. Males of the Black-browed Reed Warbler Acrocephalus bistrigiceps sang actively when they were solitary, but stopped singing as soon as they had attracted a female. Males exhibited two distinct patterns of singing behaviour after the fertile period of their mates: some resumed singing, whereas others did not. Males that resumed singing acquired secondary females more frequently than those that did not sing, suggesting that resuming males seek polygynous mating. The occurrence of extra-pair fertilization was rare (6.4%) in the study population, and extra-pair young were sired by both resuming and non-resuming males. There is no strong evidence that non-resuming males compensate for their disadvantage in social mate acquisition by extra-pair paternity. Resuming males arrived at the breeding ground earlier, suggesting that they were high-quality males.     

Determination of paternity in dragonflies by Random Amplified Polymorphic DNA fingerprinting

We used Random Amplified Polymorphic DNA (RAPD) fingerprinting to address issues of paternity in two odonate species. Amplification artifacts of RAPD markers were controlled by assessing paternity patterns relative to the banding patterns generated by quantitative mixtures of DNA from putative parents ('synthetic offspring'). In the aeshnid dragonfly Anax parthenope , for which the mating histories of both males and females were unknown, we found strong evidence for complete paternity success for the contact guarding male. In the highly polygamous libellulid dragonfly Orthetrum coerulescens , we detected and quantified mixed paternity in sequentially produced offspring clutches and demonstrated that fertilization success is correlated with the duration of copulation. Our results suggest that RAPD fingerprinting is suitable to address issues of paternity in systems which are genetically uncharacterized and produce large offspring clutches.