Song Richness Index: A measure to understand the diversity and repetition of notes in a birdsong

Birdsong plays an important role in mate attraction and territorial defense. Many birds, especially Passerines, produce varying sequences of multiple notes resulting in complex songs. Studying the diversity of notes within these songs can give insights into an individuals reproductive fitness. We first looked at the previously described and commonly used diversity measures to understand the possible case-specific limitations. We then developed a new diversity measure- Song Richness Index (SRI). We compared SRI with three measures of diversity using all possible combinations of notes to understand the case-specific advantages and limitations of all approaches. Simulating all possible combinations gave us insights into how each diversity measure works in a real scenario. SRI showed an advantage over conventional measures of diversity like Note Diversity Index (NDI), Shannons Equitability (SH), and Simpsons Diversity (SI), especially in the cases where songs are made up of only one type of repetitive note.

Immunolabeling provides evidence for subregions in the songbird nucleus accumbens and suggests a context-dependent role in song in male European starlings (Sturnus vulgaris)

Birdsong is well known for its role in mate attraction during the breeding season. However, many birds, including European starlings (Sturnus vulgaris), also sing outside the breeding season as part of large flocks. Song in a breeding context can be extrinsically rewarded by mate attraction; however, song in non-breeding flocks, referred to here as gregarious song, results in no obvious extrinsic reward and is proposed to be intrinsically rewarded. The nucleus accumbens (NAc) is a brain region well-known to mediate reward and motivation, which suggests it is an ideal candidate to regulate reward associated with gregarious song. The goal of this study was to provide new histochemical information on the songbird NAc and its subregions (rostral pole, core, and shell), and to begin to determine subregion-specific contributions to gregarious song in male starlings. We examined immunolabeling for tyrosine hydroxylase (TH), neurotensin, and enkephalin (ENK) in NAc. We then examined the extent to which gregarious and sexually-motivated song differentially correlated with immunolabeling for the immediate early genes FOS and ZENK in each subdivision of NAc. We found that TH and ENK labeling within subregions of the starling NAc was generally similar to patterns seen in the core and shell of NAc in mammals and birds. Additionally, we found that gregarious song, but not sexually-motivated song, positively correlated with FOS in all NAc subregions. Our observations provide further evidence for distinct subregions within the songbird NAc and suggest the NAc may play an important role in regulating gregarious song in songbirds.

“Behind the Façade: Motivations for Cosmetic Usage by Women”

Given the wealth of literature on appearance manipulation generally, it is, perhaps, surprising that cosmetic usage receives so little empirical attention, and perhaps reflects a patriarchal approach to “appropriate” research areas. Incorporating a postfeminist approach, the current study aims to address, in part, this lacuna by providing a contemporary synopsis of the various and diverse motivations for cosmetic usage. Online, written responses to a semi-structured questionnaire were collected. In response to six broad questions, for example, “Why do you currently use cosmetics?”, respondents were encouraged to write, in as much detail as they liked, on their motivations for using cosmetics. Thematic analysis, using deductive and inductive approaches, revealed four main themes: “Multiple selves”—Conformity, Impression Management, and Judgment; Enhancement and Confidence; Fun, Creativity and Well-being; and Signification and Identity. Whilst some of these themes had been anticipated and, indeed, sign-posted in prior literature, the weight of interest in particular areas was unexpected (e.g., in terms of Fun, Creativity, and Well-being), whilst other areas did not receive the expected attention (e.g., in mate attraction). Additionally, and worthy of future research, entirely new areas also emerged (e.g., cosmetics for fun and creativity).

Blinded by the Light: Artificial Light Lowers Mate Attraction Success in Female Glow-Worms (Lampyris noctiluca L.)

Nocturnal light pollution from anthropogenic origin is increasing worldwide and is recognised as a major threat for nocturnal biodiversity. We studied the impact of artificial light on the mate attraction success of female common glow-worms (Lampyris noctiluca L.) by daily monitoring their glowing status in the field, acting as a proxy for mating status throughout the mating season. We found that females in dark surroundings typically stopped glowing after one night, indicating that they had mated, while females in illuminated areas glowed for significantly more nights, in some cases up to 15 nights. Our study confirms previous findings and hypotheses that females exposed to artificial light suffer from a reduced mate attraction success with a negative impact on populations.

Correction to: Mate attraction, chemical defense, and competition avoidance in the parasitoid wasp Leptopilina pacifica

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