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1. Orphaning stunts growth in wild African elephants

   https://doi.org/10.1093/conphys/coac053  

   Parker, Jenna M; Wittemyer, George (January 2022, Conservation Physiology)

   Fuller, Andrea (Ed.)

   Orphans of several species suffer social and physiological consequences such as receiving more aggression from conspecifics and lower survival. One physiological consequence of orphaning, stunted growth, has been identified in both humans and chimpanzees, but has not been assessed in a non-primate species. Here, we tested whether wild African elephant orphans show evidence of stunted growth. We measured individually known female elephants in the Samburu and Buffalo Springs National Reserves of Kenya, with a rangefinder capable of calculating height, to estimate a von Bertalanffy growth curve for female elephants of the study population. We then compared measurements of known orphans and non-orphans of various ages, using a Bayesian analysis to assess variation around the derived growth curve. We found that orphans are shorter for their age than non-orphans. However, results suggest orphans may partially compensate for stunting through later growth, as orphans who had spent a longer time without their mother had heights more similar to non-orphans. More age mates in an individual’s family were associated with taller height, suggesting social support from peers may contribute to increased growth. Conversely, more adult females in an individual’s family were associated with shorter height, suggesting within-group competition for resources with older individuals may reduce juvenile growth. Finally, we found a counterintuitive result that less rainfall in the first 6 years of life was correlated with taller height, potentially reflecting the unavoidable bias of measuring individuals who were fit enough to survive conditions of low rainfall as young calves. Reduced growth of individuals has been shown to reduce survival and reproduction in other species. As such, stunting in wildlife orphans may negatively affect fitness and represents an indirect effect of ivory poaching on African elephants. 

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2. Determinants of elephant foraging behaviour in a coupled human‐natural system: Is brown the new green?

   https://doi.org/10.1111/1365-2656.12971  

   Branco, Paola_S; Merkle, Jerod_A; Pringle, Robert_M; Pansu, Johan; Potter, Arjun_B; Reynolds, Alana; Stalmans, Marc; Long, Ryan_A; Fryxell, ed., John (March 2019, Journal of Animal Ecology)

   Abstract Crop raiding by wildlife poses major threats to both wildlife conservation and human well‐being in agroecosystems worldwide. These threats are particularly acute in many parts of Africa, where crop raiders include globally threatened megafauna such as elephants, and where smallholder agriculture is a primary source of human livelihood. One framework for understanding herbivore feeding behaviour, the forage‐maturation hypothesis, predicts that herbivores should align their movements with intermediate forage biomass (i.e., peak green‐up); this phenomenon is known as “surfing the green wave.” Crop‐raiding elephants, however, often consume not just foliage, but also fruits and tubers (e.g., maize and potatoes), which generally mature after seasonal peaks in photosynthetic activity. Thus, although elephants have been reported to surf the green wave in natural habitats, they may utilize a different strategy in cultivated landscapes by selecting crops that are “browning down.”We sought to understand the factors that underpin movement of elephants into agricultural landscapes.In Mozambique's Gorongosa National Park, we used movement data from GPS‐collared elephants, together with precipitation records, remotely sensed estimates of landscape greenness (NDVI), DNA‐based diet analysis, measurements of plant nutritional quality and survey‐based metrics of crop availability to understand spatiotemporal variation in elephant crop‐raiding behaviour.Elephants tracked peak NDVI while foraging inside the Park. During the dry season, however, when NDVI within the Park declined and availability of mature crops was high, crop raiding increased dramatically, and elephants consistently selected crop plants that were browning down while foraging in cultivated landscapes. Crops contained significantly higher digestible energy than wild food plants, but comparable (and sometimes lower) levels of digestible protein, suggesting that this foraging strategy maximized energy rather than protein intake.Our study is the first to combine GPS tracking data with high‐resolution diet analysis and community‐based reporting of crop availability to reveal fine‐scale plasticity in foraging behaviour of elephants at the human–wildlife interface. Our results extend the forage‐maturation hypothesis by showing that elephants surf waves of plant brown‐down in cultivated landscapes. These findings can aid efforts to reduce human–elephant conflict by enabling wildlife managers to prioritize mitigation actions in time and space with limited resources. 

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3. Natal Kicks from the Galactic Center and Implications on Their Environment and for the Nancy Grace Roman Space Telescope

   https://doi.org/10.3847/1538-4357/ad55ee  

   Jurado, Carlos; Naoz, Smadar; Lam, Casey Y; Hoang, Bao-Minh (August 2024, The Astrophysical Journal)

   Abstract Most galaxies, including the Milky Way, harbor a central supermassive black hole (SMBH) weighing millions to billions of solar masses. Surrounding these SMBHs are dense regions of stars and stellar remnants, such as neutron stars (NSs) and black holes (BHs). NSs and possibly BHs receive large natal kicks at birth on the order of hundreds of kilometers per second. The natal kicks that occur in the vicinity of an SMBH may redistribute the orbital configuration of the compact objects and alter their underlying density distribution. We model the effects of natal kicks on a Galactic center (GC) population of massive stars and stellar binaries with different initial density distributions. Using observational constraints from stellar orbits near the GC, we place an upper limit on the steepness of the initial stellar profile and find it to be core-like. In addition, we predict that 30%–70% of compact objects become unbound from the SMBH due to their kicks and will migrate throughout the Galaxy. Different BH kick prescriptions lead to distinct spatial and kinematic distributions. We suggest that the Nancy Grace Roman Space Telescope may be able to distinguish between these distributions and thus be able to differentiate between natal kick mechanisms. 

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4. Prior parental experience attenuates hormonal stress responses and alters hippocampal glucocorticoid receptors in biparental rock doves

   https://doi.org/10.1242/jeb.244820  

   Farrar, Victoria S.; Morales Gallardo, Jaime; Calisi, Rebecca M. (December 2022, Journal of Experimental Biology)

   ABSTRACT In the face of challenges, animals must balance investments in reproductive effort versus their own survival. Physiologically, this trade-off may be mediated by glucocorticoid release by the hypothalamic–pituitary–adrenal axis and prolactin release from the pituitary to maintain parental care. The degree to which animals react to and recover from stressors likely affects maintenance of parental behavior and, ultimately, fitness. However, less is known about how gaining parental experience may alter hormonal stress responses and their underlying neuroendocrine mechanisms. To address this gap, we measured the corticosterone (CORT) and prolactin (PRL) stress response in individuals of both sexes of the biparental rock dove (Columba livia) that had never raised chicks versus birds that had fledged at least one chick. We measured both CORT and PRL at baseline and after an acute stressor (30 min restraint). We also measured negative feedback ability by administering dexamethasone, a synthetic glucocorticoid that suppresses CORT release, and measured CORT and PRL after 60 min. All hormones were measured when birds were not actively nesting to assess whether effects of parental experience extend beyond the breeding bout. Experienced birds had lower stress-induced and negative-feedback CORT, and higher stress-induced PRL than inexperienced birds. In a separate experiment, we measured glucocorticoid receptor subtype expression in the hippocampus, a key site of negative feedback regulation. Experienced birds showed higher glucocorticoid receptor expression than inexperienced controls, which may mediate their ability to attenuate CORT release. Together, these results shed light on potential mechanisms by which gaining experience may improve parental performance and fitness. 

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5. Family Cohesion Moderates the Relation between Parent–Child Neural Connectivity Pattern Similarity and Youth's Emotional Adjustment

   https://doi.org/10.1523/JNEUROSCI.0349-23.2023  

   Zhou, Zexi; Chen, Ya-Yun; Yang, Beiming; Qu, Yang; Lee, Tae-Ho (July 2023, The Journal of Neuroscience)

   Despite a recent surge in research examining parent–child neural similarity using fMRI, there remains a need for further investigation into how such similarity may play a role in children's emotional adjustment. Moreover, no prior studies explored the potential contextual factors that may moderate the link between parent–child neural similarity and children's developmental outcomes. In this study, 32 parent–youth dyads (parents:M_age= 43.53 years, 72% female; children:M_age= 11.69 years, 41% female) watched an emotion-evoking animated film while being scanned using fMRI. We first quantified how similarly emotion network interacts with other brain regions in responding to the emotion-evoking film between parents and their children. We then examined how such parent–child neural similarity is associated with children's emotional adjustment, with attention to the moderating role of family cohesion. Results revealed that higher parent–child similarity in functional connectivity pattern during movie viewing was associated with better emotional adjustment, including less negative affect, lower anxiety, and greater ego resilience in youth. Moreover, such associations were significant only among families with higher cohesion, but not among families with lower cohesion. The findings advance our understanding of the neural mechanisms underlying how children thrive by being in sync and attuned with their parents, and provide novel empirical evidence that the effects of parent–child concordance at the neural level on children's development are contextually dependent. SIGNIFICANCE STATEMENTWhat neural processes underlie the attunement between children and their parents that helps children thrive? Using a naturalistic movie-watching fMRI paradigm, we find that greater parent–child similarity in how emotion network interacts with other brain regions during movie viewing is associated with youth's better emotional adjustment including less negative affect, lower anxiety, and greater ego resilience. Interestingly, these associations are only significant among families with higher cohesion, but not among those with lower cohesion. Our findings provide novel evidence that parent–child shared neural processes to emotional situations can confer benefits to children, and underscore the importance of considering specific family contexts in which parent–child neural similarity may be beneficial or detrimental to children's development, highlighting a crucial direction for future research. 

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