Climate-induced reaction norms for life-history traits in pythons

Climate change modelers predict increasingly frequent “extreme events,” so it is critical to quantify whether organismal responses (such as reproductive output) measured over the range of usual climatic conditions can predict responses under more extreme conditions. In a 20-year field study on water pythons (Liasis fuscus), we quantified the effects of climatically driven annual variation in food supply on demographic traits of female pythons (feeding rate, body size, body mass, and reproductive output). Reaction norms linking food supply to feeding rates and residual body mass were broadly linear, whereas norms linking food supply to female body size became curvilinear when a dramatic (flooding-induced) famine reduced the mean body size at sexual maturity. Thus, the reaction norms recorded over 16 years of “normal” (albeit highly variable) climatic conditions gave little insight into the population's response to a more extreme nutritional crisis.

‘Subtypes’ in the presentation of autistic traits in the general adult population

The present study examined the presentation of autistic traits in a large adult population sample (n = 2,343). Cluster analysis indicated two subgroups with clearly distinguishable trait profiles. One group (n = 1,059) reported greater social difficulties and lower detail orientation, while the second group (n = 1,284) reported lesser social difficulties and greater detail orientation. We also report a three-factor solution for the autism-spectrum quotient, with two, related, social-themed factors (Sociability and Mentalising) and a third non-social factor that varied independently (Detail Orientation). These results indicate that different profiles of autistic characteristics tend to occur in the adult nonclinical population. Research into nonclinical variance in autistic features may benefit by considering social- and detail-related trait domains independently.

Overlap between autistic and schizotypal personality traits is not accounted for by anxiety and depression.

Autism spectrum and schizophrenia spectrum disorders are classified separately in the DSM-5, yet research indicates that these two disorders share overlapping features. The aim of the present study was to examine the overlap between autistic and schizotypal personality traits and whether anxiety and depression act as confounding variables in this relationship within a non-clinical population. One hundred and forty-four adults completed the Autism Spectrum Quotient and the Schizotypal Personality Questionnaire and the Depression Anxiety Stress Scales-21. A number of associations were seen between autistic and schizotypal personality traits. However, negative traits were the only schizotypal feature to uniquely predict global autistic traits, thus highlighting the importance of interpersonal qualities in the overlap of autistic and schizotypal characteristics. The inclusion of anxiety and depression did not alter relationships between autistic and schizotypal traits, indicating that anxiety and depression are not confounders of this relationship. These findings have important implications for the conceptualisation of both disorders.

The expression of pre- and postcopulatory sexually selected traits reflects levels of dietary stress in guppies

Environmental and ecological conditions can shape the evolution of life history traits in many animals. Among such factors, food or nutrition availability can play an important evolutionary role in moderating an animal's life history traits, particularly sexually selected traits. Here, we test whether diet quantity and/or composition in the form of omega-3 long chain polyunsaturated fatty acids (here termed 'n3LC') influence the expression of pre- and postcopulatory traits in the guppy (Poecilia reticulata), a livebearing poeciliid fish. We assigned males haphazardly to one of two experimental diets supplemented with n3LC, and each of these diet treatments was further divided into two diet 'quantity' treatments. Our experimental design therefore explored the main and interacting effects of two factors (n3LC content and diet quantity) on the expression of precopulatory (sexual behaviour and sexual ornamentation, including the size, number and spectral properties of colour spots) and postcopulatory (the velocity, viability, number and length of sperm) sexually selected traits. Our study revealed that diet quantity had significant effects on most of the pre- and postcopulatory traits, while n3LC manipulation had a significant effect on sperm traits and in particular on sperm viability. Our analyses also revealed interacting effects of diet quantity and n3LC levels on courtship displays, and the area of orange and iridescent colour spots in the males' colour patterns. We also confirmed that our dietary manipulations of n3LC resulted in the differential uptake of n3LC in body and testes tissues in the different n3LC groups. This study reveals the effects of diet quantity and n3LC on behavioural, ornamental and ejaculate traits in P. reticulata and underscores the likely role that diet plays in maintaining the high variability in these condition-dependent sexual traits.