Beyond the prey: male spiders highly invest in silk when producing worthless gifts

In the spider Paratrechalea ornata, males have two gift-giving mating tactics, offering either a nutritive (prey) or a worthless (prey leftovers) silk wrapped gift to females. Both gift types confer similar mating success and duration and afford males a higher success rate than when they offer no gift. If this lack of difference in the reproductive benefits is true, we would expect all males to offer a gift but some males to offer a worthless gift even if prey are available. To test this, we allowed 18 males to court multiple females over five consecutive trials. In each trial, a male was able to produce a nutritive gift (a live housefly) or a worthless gift (mealworm exuviae). We found that, in line with our predictions, 20% of the males produced worthless gifts even when they had the opportunity to produce a nutritive one. However, rather than worthless gifts being a cheap tactic, they were related to a higher investment in silk wrapping. This latter result was replicated for worthless gifts produced in both the presence and absence of a live prey item. We propose that variation in gift-giving tactics likely evolved initially as a conditional strategy related to prey availability and male condition in P. ornata. Selection may then have favoured silk wrapping as a trait involved in female attraction, leading worthless gift-giving to invade.

Menstruation and menopause in autistic adults: Periods of importance?

Autism spectrum conditions were once seen as a predominantly male condition. This has caused a paucity of information on common events in the lives of women, such as menstruation and menopause. Some smaller studies indicate that autistic women might suffer from increased difficulties surrounding these events. This study aims to investigate whether autistic women experience more frequent premenstrual dysphoric disorder, and increased complaints surrounding menopause. In partly overlapping samples (premenstrual dysphoric disorder, n = 70, nASC = 28, ncomparisons = 42; menopause, n = 65, nASC = 30, ncomparisons = 35), we investigated premenstrual dysphoric disorder prevalence and menopausal complaints. In 70 individuals, we did not find an increased prevalence of premenstrual dysphoric disorder in autistic women (14.3%) compared with non-autistic women (9.5%). In 65 women aged 40 years and above, we found that autistic women did experience higher levels of menopausal complaints. In autistic women, higher menopausal complaints were associated with higher levels of depression and autistic traits. In non-autistic women, menopausal complaints were associated with increased inattention, hyperactivity/impulsivity (i.e. attention deficit hyperactivity disorder traits), and depression. With this work, we show the important role that major reproductive milestones can have in an autistic woman’s life. Lay abstract Autism spectrum conditions were once seen as a predominantly male condition, but this has caused research to have little focus on women. Therefore, little is known about menstruation and menopause in autism spectrum conditions. Some smaller studies indicate that autistic individuals might suffer from increased difficulties surrounding these events. This study aimed to investigate whether autistic women experience more frequent premenstrual dysphoric disorder, causing extreme physical, emotional, and functional impairment. In a partly overlapping sample, we also examined whether women with autism spectrum condition experience increased complaints surrounding menopause. We did not find an increased prevalence of premenstrual dysphoric disorder in autism spectrum conditions (14.3%) compared with non-autistic women (9.5%). Those with autism spectrum conditions did experience increased menopausal complaints. These menopausal complaints were associated with higher levels of depression and autistic traits. In non-autistic women, menopausal complaints were associated with increased inattention, hyperactivity/impulsivity (i.e. attention deficit hyperactivity disorder traits), and depression. With this work, we show the important role that major reproductive milestones can have in an autistic woman’s life.

Male size mediates plastic response to winner-loser effects for some sexually selected traits

The outcomes of fights often affect the fitness of males by determining their access to mates. ‘Winner-loser’ effects, where winners often win their next contest, but losers tend to lose, can therefore influence how males allocate resources towards traits under pre- and post-copulatory sexual selection. We experimentally manipulated the winning/losing experiences of size-matched male Gambusia holbrooki for either a day, a week or three weeks to test whether prior winning/losing experiences differentially affect the plasticity of male investment into either mating effort (pre-copulatory) or ejaculates (post-copulatory). Winners had better pre-copulatory outcomes than losers for three of the four traits we measured: number of mating attempts, number of successful attempts, and time spent with the female. Winners also produced faster sperm than losers, but there was no difference in total sperm counts. Interestingly, absolute male size, an important predictor of fighting success, mediated the effect of winning or losing on how long males then spent near a female. Smaller winners spent more time with the female than did larger winners, suggesting that how males respond to prior social experiences is size-dependent. We discuss the general importance of controlling for inherent male condition when comparing male investment into condition-dependent traits.

Conspecific aggression strategies are conditioned by environmental, social and intrinsic variables in breeding blue tits Cyanistes caeruleus

Territorial behaviour arises as a strategy of ensuring individuals’ access to a variety of potentially limiting resources. While aggressiveness is a well-studied widespread trait across taxa, the mechanisms that allow for a range of aggressive phenotypes to coexist in the wild remains unclear. In this study, we analyse environmental, social and intrinsic variables that can modulate the expression of different strategies of male–male aggressiveness. Furthermore, through network analysis we explore the role of this trait in the establishment of territories during the breeding season as the intensity of different aggressiveness strategies may limit or grant access to resources. Simulating territorial intrusions during the early incubation period, we assessed the aggressiveness of breeding male blue tits (Cyanistes caeruleus). We defined three types of conspecific aggressiveness (nonconfrontational intimidating, nonconfrontational cautious and confrontational) and analysed the effect of habitat structure, territory quality, presence of other breeding species and male condition on the type and intensity of the aggressive display. The results obtained suggest that yearling males rely on intimidating behaviour more than older males, that perform more cautious displays. Furthermore, smaller and heavier males opted for confrontational strategies. The density and nature of neighbours, as well as the territory quality and the habitat structure, also conditioned the intensity and type of display. Surprisingly, the network analysis revealed that the intensity of male–male aggressive displays did not condition the establishment of breeding territories. Our results suggest that aggressiveness is a context-specific trait shaped by a complex array of environmental and intrinsic parameters.

Autism in girls and the pre-referral environment

AimsThis literature review sought to identify and highlight any sex specific factors in the diagnosis of autism spectrum conditions during the pre-referral period which might affect diagnosis rates in ASD in girls. The null hypothesis was that there are no sex specific factors that affect referral and diagnosis of ASD in girls.BackgroundHistorically, boys are diagnosed with ASD more than girls but rates vary depending on clinical population characteristics. Diagnosis trends continue to demonstrate a large male excess. The concept of autism as a predominantly male condition has been challenged and there is increased focus on females with high functioning autism who are not being detected as easily.Various theories exist as to why this is the case.There are high rates of suicidality in ASD and risk of death by suicide is higher in ASD women (the reciprocal of the suicide rates in general population where more men complete suicide). Women with high functioning autism represent an at risk group. Undetected autism in females may be complicated by ‘camouflaging’ or masking of symptoms which puts a large strain on individuals functioning and mental health. Costs to society and the individual are large.However, early identification and intervention improves outcomes such as activities of daily living and social behaviours.MethodAn electronic literature search was completed using MEDLINE, PsycINFO and EMBASE in November 2018. Key terms were: (‘child*’ OR ‘adolescent’ OR ‘young pe*’) AND (‘ASD’ OR ‘autism’ OR ‘asperger*’ OR ‘high functioning*’ OR ‘PDD’ OR ‘Pervasive developmental*’) AND (‘girl*’ OR ‘sex’ OR ‘gender’). Papers were excluded on a number of grounds.Result11 papers were included in the review from an initial 2823 abstracts.ConclusionA number of papers highlighted important learning points. Some of the more original conclusions included that we require more studies comparing populations of girls with ASD to high risk, high functioning girls and female controls to clarify features particular to the ‘female phenotype’. Delays in diagnosis in girls appears to pre-date assessment so further thought on how to educate and support referral sources (caregivers and schools) on how to identify girls with autism is recommended and would be informed by further research focus on the previous point. Active case ascertainment should be considered in future research and follow-up of girls who do not receive a diagnosis at initial assessment were additional learning points that came from the review.

Condition-dependent differences in male vibratory pre-copulatory and copulatory courtship in a nuptial gift-giving spider

Condition-dependent secondary sexual traits and signals are often crucial for mate choice decisions. Nuptial gifts, provided by the male to the female during mating, may represent an indicator of male condition, especially if production of the gift is energetically costly. Additionally, other signalling modalities may well play a role in mate choice in such systems. Females of the nursery web spider Pisaura mirabilis preferably mate with males that provide a prey item wrapped in silk. Apart from the nuptial gift, vibrational signals employed during courtship and mating may reveal additional information about male condition. We tested condition-dependence of male vibrational signals of well-fed versus starved males, when in contact with female dragline silk and during mating trials. Our results show that vibrational signals are produced in P. mirabilis, both during pre-copulatory courtship and during copulation. Male courtship signals were condition-dependent: males in good condition initiated signalling earlier and emitted more vibrational pulses than poor-condition males. They were also more likely to be accepted by the female for copulation. We additionally identified vibrational signals during copulation. These signals were different from pre-copulatory courtship vibrations but did not differ between the treatment groups. This study shows that vibrational communication plays an important role before and during copulation in P. mirabilis. It sets the stage for further experiments on spider biotremology associated with nuptial gift giving behaviour. Significance statement Male courtship behaviour can indicate a male’s condition and quality and be subject to female mate choice. Vibrational communication during mating plays a crucial role in many animal species. Spiders are known to be extremely sensitive towards vibrations, and there is evidence that vibratory signals are also used during courtship. Here, we study the nuptial gift-giving spider Pisaura mirabilis in which courtship entails providing a nuptial gift by the male to the female. The gift quality determines on the probability and duration of mating. We investigated the role of vibrational behaviour in this species by standardizing nuptial gifts. Our study demonstrates that vibratory signals comprise information about the male’s condition, that signals are also produced during mating and that courtship and copulatory signals are strikingly different. We suggest that vibrational communication provides important condition-dependent traits for female mate choice in addition to the nuptial gift.

Influences of male age, mating history and starvation on female post mating aggression and feeding in Drosophila

Mating changes female behaviour and physiology across a wide range of taxa, with important effects for male and female fitness. These changes are often induced by components of the male ejaculate, such as sperm and seminal fluid proteins.However, males can vary significantly in their ejaculates, due to factors such as age, mating history, or nutritional status. This male variation may therefore lead to variation in the strength of responses males can stimulate in females, with alterations in fitness outcomes for both sexes.Using the fruit fly, Drosophila melanogaster, we tested whether three aspects of male condition shape an important, but understudied, post-mating response – increased female-female aggression.We found that females mated to old males fought less than females mated to young males. This effect was exacerbated in mates of old, sexually active males, but there was no effect of male starvation status on mating-induced female aggression. There was also a significant effect of age and mating history on female post-mating feeding duration.Our results add to a growing body of literature that variation in male condition can shape sexual selection through post-mating responses in females, including female-female interactions. Studying such variation may therefore be useful for understanding how the condition of sex affects the behaviour of the other.