Dynamic mimicry in an Indo-Malayan octopus

During research dives in Indonesia (Sulawesi and Bali), we filmed a distinctive long-armed octopus, which is new to science. Diving over 24 h periods revealed that the 'mimic octopus' emerges during daylight hours to forage on sand substrates in full view of pelagic fish predators. We observed nine individuals of this species displaying a repertoire of postures and body patterns, several of which are clearly impersonations of venomous animals co-occurring in this habitat. This 'dynamic mimicry' avoids the genetic constraints that may limit the diversity of genetically polymorphic mimics but has the same effect of decreasing the frequency with which predators encounter particular mimics. Additionally, our observations suggest that the octopus makes decisions about the most appropriate form of mimicry to use, allowing it to enhance further the benefits of mimicking toxic models by employing mimicry according to the nature of perceived threats

Female impersonation as an alternative reproductive strategy in giant cuttlefish

Out of all the animals, cephalopods possess an unrivalled ability to change their shape and body patterns. Our observations of giant cuttlefish (Sepia apama) suggest this ability has allowed them to evolve alternative mating strategies in which males can switch between the appearance of a female and that of a male in order to foil the guarding attempts of larger males. At a mass breeding aggregation in South Australia, we repeatedly observed single small males accompanying mating pairs. While doing so, the small male assumed the body shape and patterns of a female. Such males were never attacked by the larger mate-guarding male. On more than 20 occasions, when the larger male was distracted by another male intruder, these small males, previously indistinguishable from a female, were observed to change body pattern and behaviour to that of a male in mating display. These small males then attempted to mate with the female, often with success. This potential for dynamic sexual mimicry may have played a part in driving the evolution of the remarkable powers of colour and shape transformation which characterize the cephalopods

Nuptial gifts fail to resolve a sexual conflict in an insect

Background Because of the potential benefits to individuals of saving investment for future mating opportunities, there is conflict between mates over most aspects of reproduction. Males of many species transfer compounds in the ejaculate that manipulate female reproductive physiology to increase male reproductive success. These seminal compounds are often associated with direct and/or indirect costs to females. In contrast, in some species ejaculates also contain nutrients used by females for somatic maintenance and increased reproductive output. In general, the extent to which male seminal components are detrimental or beneficial to females is poorly understood, and interactions between seminal compounds with different effects have been almost completely neglected. Here we examine the impact of male receptivity-suppressing factors and nutrient donations on female longevity and lifetime reproductive output in the bushcricket Requena verticalis. Results We show that receiving multiple ejaculates reduces longevity in female R. verticalis, indicating a cost of male derived receptivity-suppressing compounds. Consumption of male nutrient donations does not appear to ameliorate this longevity cost, and there was no effect of nutrient provisioning on female lifetime fecundity. Conclusion These results indicate that nutrient provisioning does not provide a resolution to sexual conflict over female receptivity in this bushcricket species

Do Genetic Diversity Effects Drive the Benefits Associated with Multiple Mating? A Test in a Marine Invertebrate

Background: Mothers that mate with multiple males often produce higher quality offspring than mothers that mate with a single male. By engaging in polyandry, mothers may increase their chances of mating with a compatible male or promote sperm competition - both of which act to increase maternal fitness via the biasing of the paternity of offspring. Surprisingly, mating with multiple males, can carry benefits without biasing paternity and may be due simply to differences in genetic diversity between monandrous and polyandrous clutches but role of genetic diversity effects in driving the benefits of polyandry remains poorly tested. Disentangling indirect, genetic benefits from genetic diversity effects is challenging but crucial if we are to understand the selection pressures acting to promote polyandry. Methodology/Principal Findings: Here, we examine the post-fertilisation benefits of accessing the sperm of multiple males in an externally fertilising polychaete worm. Accessing the sperm of multiple males increases offspring performance but this benefit was driven entirely by genetic diversity effects and not by the biasing of paternity at fertilisation. Conclusions/Significance: Previous studies on polyandry should be interpreted cautiously as genetic diversity effects alone can explain the benefits of polyandry yet these diversity effects may be difficult to disentangle from other mechanisms. We suggest that future studies use a modified experimental design in order to discriminate between genetic diversity effects and indirect, genetic benefits

Wild cricket social networks show stability across generations

Funding for this research was provided by NERC (studentship no.: NE/H02249X/1; grant no.: NE/H02364X/1).Peer reviewedPublisher PD

Female Field Crickets Incur Increased Parasitism Risk When Near Preferred Song

Female animals often prefer males with conspicuous traits because these males provide direct or indirect benefits. Conspicuous male traits, however, can attract predators. This not only increases the risk of predation for conspicuous males but also for the females that prefer them. In the variable field cricket, Gryllus lineaticeps, males that produce preferred song types provide females with greater material benefits, but they are also more likely to attract lethal parasitoid flies. First, we conducted a field experiment that tested the hypothesis that females have a greater risk of fly parasitism when in association with preferred high chirp rate males. Females were nearly twice as likely to be parasitized when caged with high chirp rate song than when caged with low chirp rate song. Females may thus be forced to trade off the quality of the benefits they receive from mating with preferred males and the risk of being killed by a predator when near these males. Second, we assessed female parasitism rates in a natural population. Up to 6% of the females were parasitized in field samples. Because the females we collected could have become parasitized had they not been collected, this provides a minimum estimate of the female parasitism rate in the field. In a laboratory study, we found no difference in the proportion of time parasitized and unparasitized females spent hiding under shelters; thus, differences in activity patterns do not appear to have biased our estimate of female parasitism rates. Overall, our results suggest that female association costs have the potential to shape the evolution of female mating preferences

How many scientists fabricate and falsify research? A systematic review and meta-analysis of survey data. PLoS One.

Abstract The frequency with which scientists fabricate and falsify data, or commit other forms of scientific misconduct is a matter of controversy. Many surveys have asked scientists directly whether they have committed or know of a colleague who committed research misconduct, but their results appeared difficult to compare and synthesize. This is the first metaanalysis of these surveys. To standardize outcomes, the number of respondents who recalled at least one incident of misconduct was calculated for each question, and the analysis was limited to behaviours that distort scientific knowledge: fabrication, falsification, ''cooking'' of data, etc… Survey questions on plagiarism and other forms of professional misconduct were excluded. The final sample consisted of 21 surveys that were included in the systematic review, and 18 in the meta-analysis. A pooled weighted average of 1.97% (N = 7, 95%CI: 0.86-4.45) of scientists admitted to have fabricated, falsified or modified data or results at least once -a serious form of misconduct by any standard-and up to 33.7% admitted other questionable research practices. In surveys asking about the behaviour of colleagues, admission rates were 14.12% (N = 12, 95% CI: 9.91-19.72) for falsification, and up to 72% for other questionable research practices. Meta-regression showed that self reports surveys, surveys using the words ''falsification'' or ''fabrication'', and mailed surveys yielded lower percentages of misconduct. When these factors were controlled for, misconduct was reported more frequently by medical/ pharmacological researchers than others. Considering that these surveys ask sensitive questions and have other limitations, it appears likely that this is a conservative estimate of the true prevalence of scientific misconduct

How many scientists fabricate and falsify research? A systematic review and meta-analysis of survey data. PLoS One.

Abstract The frequency with which scientists fabricate and falsify data, or commit other forms of scientific misconduct is a matter of controversy. Many surveys have asked scientists directly whether they have committed or know of a colleague who committed research misconduct, but their results appeared difficult to compare and synthesize. This is the first metaanalysis of these surveys. To standardize outcomes, the number of respondents who recalled at least one incident of misconduct was calculated for each question, and the analysis was limited to behaviours that distort scientific knowledge: fabrication, falsification, ''cooking'' of data, etc… Survey questions on plagiarism and other forms of professional misconduct were excluded. The final sample consisted of 21 surveys that were included in the systematic review, and 18 in the meta-analysis. A pooled weighted average of 1.97% (N = 7, 95%CI: 0.86-4.45) of scientists admitted to have fabricated, falsified or modified data or results at least once -a serious form of misconduct by any standard-and up to 33.7% admitted other questionable research practices. In surveys asking about the behaviour of colleagues, admission rates were 14.12% (N = 12, 95% CI: 9.91-19.72) for falsification, and up to 72% for other questionable research practices. Meta-regression showed that self reports surveys, surveys using the words ''falsification'' or ''fabrication'', and mailed surveys yielded lower percentages of misconduct. When these factors were controlled for, misconduct was reported more frequently by medical/ pharmacological researchers than others. Considering that these surveys ask sensitive questions and have other limitations, it appears likely that this is a conservative estimate of the true prevalence of scientific misconduct

Why do male Callosobruchus maculatus harm their mates?

Males of the bruchid beetle Callosobruchus maculatus have spines on their intromittent organs that puncture the female reproductive tract during mating. Females kick their mates during copulation. If females are prevented from kicking the males, copulations last longer and the injuries females sustain are more severe. We tested whether or not these injuries represent real fitness costs that can be mitigated by kicking and also what males gain by inflicting them. Our results show that females do indeed suffer lowered lifetime fecundity if they are prevented from kicking. However, we could find no evidence that males gain benefits through harming their mates. It has been suggested that the way females respond to the harm may benefit the male causing it. Injured females may be less willing to remate to avoid sustaining further injuries, or they may respond by increasing their rate of oviposition if they perceive the injuries as a threat to their survival. In our study, however, females that were prevented from kicking did not respond by delaying remating or increasing their rate of oviposition. Furthermore, preventing females from kicking during their second copulation did not make their second mates more successful in sperm competition. This suggests that the spines have evolved for other reasons than harming the females, such as serving as an anchor during copulation, and that the harm they cause is a side effect of a male adaptation and is not itself adaptive for either sex