An examination of nest-building behaviour using five different nesting materials in C57BL/6J and BALB/c mice

The aim of our study was to assess the nest-building behaviour of two mouse (Mus musculus) strains using different nesting materials and examine possible sex- and housing-specific effects. Adult mice of two strains (C57BL/6J; n = 64 and BALB/cAnNCrl; n = 99) were randomly allocated to the following housing groups: single-housed male, single-housed female, pair-housed male and pair-housed female. One of the following nest-building materials was placed in each home-cage in a random order: nestlets (Plexx BV, The Netherlands), cocoons (Carfil, Belgium), wooden wool, crinklets and compact (all three, Safe, Germany). The following day, nests were rated applying a nest-scoring scale ranging from 0 to 10, the nests were removed, and a different nest-building material provided. In both tested strains, nestlets achieved the highest nest-building scores when compared to the other four nest-building materials. All nest-building materials scored higher in BALB/c mice compared to C57BL/6J animals reaching statistical significance in crinklets only. Sex comparison revealed that female C57BL/6J mice only scored significantly higher using crinklets than males and BALB/c female mice were rated significantly higher using wooden wool, cocoons and compact than their male counterparts. While pair-housed C57BL/6J animals built higher-rated nests than single-housed mice in the C57BL/6J strain in all five materials tested, the scores were not significantly different in the BALB/c strain. Results of the present study reveal significant strain-, sex- and housing-related influences on the complexity of nests using different standardised building materials. Such observations need to be taken into account when planning the optimal enrichment programme for laboratory animals.

Nest-Building Effort is Not An Indicator of Male Quality In Bonelli’s Eagles, Aquila fasciata

Raptors often use a variety of materials to build their nests (natural, such as branches, but also non-natural objects), presumably due to their insulating properties, their suitability to advertise occupancy of the nest, and to decrease pathogen and parasite loads. The amount of branches used in a nest is an indicator of parental quality and is often associated with increased breeding success. However, in raptors where both sexes collaborate in nest construction, it is unclear whether the effort expended by males (taking the amount of material carried to the nest as the potential predictor) could constitute an honest signal of parental quality to female conspecifics. We examined data on sex, type of material brought to the nest, breeding experience, timing, and nest-building investment prior to egg-laying from 32 identifiable Bonelli’s Eagles (Aquila fasciata) during the pre-laying period to investigate the relative contribution of the sexes to the amount of nest material gathered. We asked: (1) whether the nest-building investment of males could provide information to the females about their quality; and (2) whether the amount of material delivered to the nest by the male was related to breeding success. Despite the considerable investment of males in nest-building during the pre-laying period, our results indicate that this effort is not a consistent indicator of male quality to the female. Therefore, male nest-building behaviour and investment by Bonelli’s Eagles cannot be considered as an extended expression of their phenotype (an extended phenotypic signal). Nest-building behaviour by males in the early and late stages of nest-building, and the fact that males were not significantly more active builders, are discussed in the contexts of signaling nest occupancy to conspecifics and competitors, the decrease of parasite loads, and the strengthening of the pair-bond during the pre-laying period.

Lower pollen nutritional quality delays nest building and egg laying in Bombus terrestris audax micro-colonies leading to reduced biomass gain

The performance of Bombus terrestris micro-colonies fed five diets differing in pollen species composition and level of nine essential amino acids (EAA; leucine, lysine, valine, arginine, isoleucine, phenylalanine, threonine, histidine, methionine) was assessed for 37 days by recording total biomass gain, nest building initiation, brood production (eggs, small and large larvae, pupae, drones), nectar, and pollen collection. Stronger colony performance was linked to higher amino acid levels but no consistent differences in biomass gain were recorded between mono- and poly-species diets. Poorest performance occurred in micro-colonies offered pure oilseed rape (OSR) pollen which contained the lowest EAA levels. Reduced micro-colony development (delayed nest initiation and lower brood production) was related to OSR proportion in the diet and lower EAA levels. Results are discussed in relation to selection of plant species in the design of habitats to promote bee populations.

Spexin modulates molecular thermogenic profile of adipose tissue and thermoregulatory behaviors

ABSTRACTThermoregulation is a physiological process by which a mammal regulates body temperature in response to its environment. Within the human body, thermoregulatory behaviors and metabolism are modulated by circulating metabolic factors. In our study, we tested the ability of the neuropeptide spexin, which shares sequence homology to galanin, to regulate these functions in female mice. Supraphysiological levels of spexin in C57BL/6 mice were insufficient to protect against diet-induced obesity after 50 days of treatment. Behavioral analysis of long-term spexin treatment appeared to modulate anxiety-like behaviors by promoting exploratory behaviors and thermoregulatory behaviors of nest building that ceased when animals were housed at thermoneutral temperatures. Upon examination of the molecular profile of brown and white adipose tissue, treatment disrupted the thermogenic profile of white adipose tissue, in which β3-adrenergic receptor expression was downregulated. Our results reveal novel functions for spexin as a modulator of thermoregulatory behaviors and adipose tissue metabolism.HighlightsSpexin treatment did not protect against diet-induced obesity in female mice.Spexin-treatment promoted thermoregulatory behaviors of nest building.Behaviors normalized when animals were housed in thermoneutral temperatures.Funding SourcesNot applicableDisclosure SummaryNothing to disclose

Behavioral Observation Procedures and Tests to Characterize the Suitability of Sows for Loose-Housed Farrowing Systems

The objective of the study was to evaluate behavioral observation procedures and tests to characterize sows’ behavior for their suitability for free farrowing systems. Nest building activity (NB), lying-down behavior (LDB), and position after lying down (PLD) were assessed. Four tests were designed to characterize the reaction of sows to a novel object and an unexpected situation (Towel Test, TT), behavior towards humans (Dummy Arm Test, DAT; Trough Cleaning Test, TCT), and behavior towards piglets (Reunion Test, RT). The study was performed on a nucleus farm in 37 batches including 771 purebred landrace sows housed in farrowing pens with short-term fixation. The assessment of NB started 2 days before the expected date of the farrowing. In 56.2% of the observations, the sows showed increased chewing activity on gunnysacks. The LDB and PLD were assessed on days 3 and 19 post partum (p.p.). In 49.1% of the observations, sows showed careful lying-down behavior. In 50.1% of cases, sows preferred the stomach-teats-position when lying down. With the DAT on day 4 p.p., in 89.3% of observations, no or only slight reactions of the sow were documented. The TT and TCT were performed on days 3 and 10 p.p. Strong defensive reactions of animals towards humans were recorded in 4.5% of the observations in the TT, and in 4.0% of the observations in the TCT. In the RT on day 3 p.p., in 61.8%, a joyful response of the sows to the reunion with their piglets was observed. This study showed that the behavioral observation procedures and designed tests are suitable to characterize sows’ behavior towards humans and piglets with regard to traits that are particularly important in systems without fixation.

Uncertainty in experts’ judgments exposes the vulnerability of research reporting anecdotes on animals’ cognitive abilities

Expertise in science, particularly in animal behaviour, may provide people with the capacity to provide better judgments in contrast to lay people. Here we explore whether experts provide a more objective, accurate and coherent evaluation of a recently reported anecdote on Atlantic puffin (Fratercula arctica) “tool use” (recorded on video) which was published in a major scientific journal but was received with some scepticism. We relied on citizen science and developed a questionnaire to measure whether experts in ethology and ornithology and lay people agree or disagree on (1) the description of the actions that they observe (the bird takes a stick in its beak), (2) the possible goal of the action (nest-building or grooming) and (3) the intentional component of the action (the bird took the stick into its beak in order to scratch itself). We hypothesised that contrary to the lay people, experts are more critical evaluators that is they are more inclined to report alternative actions, like nest building, or are less likely to attributing goal-directedness to the action in the absence of evidence. In contrast, lay people may be more prone to anthropomorphise utilising a teleological and intentional stance. Alternatively, all three groups of subjects may rely on anthropomorphism at similar levels and prior expertise does not play a significant role. We found that no major differences among the evaluators. At the group levels, respondents were relatively uncertain with regard to the action of the bird seen on the video but they showed some individual consistency with regard to the description of the action. Thus, we conclude that paradoxically, with regard to the task our experts are typically not experts in the strict sense of the definition, and suggest that anecdotal reports should not be used to argue about mental processes.