Quantifying Southern Pacific Rattlesnake (Crotalus oreganus helleri) Hunting Behavior through Community Science

It is increasingly important to study animal behaviors as these are the first responses organisms mount against environmental changes. Rattlesnakes, in particular, are threatened by habitat loss and human activity, and require costly tracking by researchers to quantify the behaviors of wild individuals. Here, we show how photo-vouchered observations submitted by community members can be used to study cryptic predators like rattlesnakes. We utilized two platforms, iNaturalist and HerpMapper, to study the hunting behaviors of wild Southern Pacific Rattlesnakes. From 220 observation photos, we quantified the direction of the hunting coil (i.e., “handedness”), microhabitat use, timing of observations, and age of the snake. With these data, we looked at whether snakes exhibited an ontogenetic shift in behaviors. We found no age differences in coil direction. However, there was a difference in the microhabitats used by juveniles and adults while hunting. We also found that juveniles were most commonly observed during the spring, while adults were more consistently observed throughout the year. Overall, our study shows the potential of using community science to study the behaviors of cryptic predators.

First records of a new color pattern in the Goldblotch Grouper, Epinephelus costae (Steindachner, 1878) (Actinopterygii: Serranidae) and first record of leucism in the European conger, Conger conger (Linnaeus, 1758) (Actinopterygii: Congridae)

In many fish, color patterns are striking features and can play an important role in both natural and sexual selection. Furthermore, details of color patterns are in some cases valid tools for species identification. However, fish can also show some genetic abnormalities, such as albinism and leucism. In this research, we report for the first time a new color pattern for Epinephelus costae (Steindachner, 1878), for which it is known an ontogenetic shift in color pattern, and the first case of leucism in Conger conger (Linnaeus, 1758).

Regenerative Crosstalk between Cardiac Cells and Macrophages

Aside from the first week postnatal, murine heart regeneration is restricted and responses to damage follow classic fibrotic remodeling. Recent transcriptomic analyses have suggested that significant crosstalk with the sterile immune response could maintain a more embryonic-like signaling network that promotes acute, transient responses. However with age, this response-likely mediated by neonatal yolk sac macrophages-then transitions to classical macrophage-mediated, cardiac fibroblast (CF)-based remodeling of the extracellular matrix (ECM) after myocardial infarction (MI). The molecular mechanisms that govern the change with age and drive fibrosis via inflammation are poorly understood. Using multiple RNA-seq datasets, we attempt to resolve the relative contributions of CFs and macrophages in the bulk healing response of regenerative (postnatal day 1) and non-regenerative hearts (postnatal day 8+). We performed an analysis of bulk RNA-seq datasets from myocardium and cardiac fibroblasts as well as a single-cell RNA-seq dataset from cardiac macrophages. MI-specific pathway differences revealed that non-regenerative hearts generated more ECM and had larger matricellular responses correlating with inflammation, produced greater chemotactic gradients to recruit macrophages, and expressed receptors for danger-associated molecular patterns at higher levels than neonates. These changes could result in elevated stress response pathways compared to neonates, converging at NF-κB and AP-1 signaling. Pro-fibrotic gene programs, which greatly diverge on day 3 post-MI, lay the foundation for chronic fibrosis, and thus postnatal hearts older than 7 days typically exhibit significantly less regeneration. Our analyses suggest that the macrophage ontogenetic shift in the heart postnatally could result in detrimental stress signaling that suppresses regeneration.

Trophic Ecology of the Cuban Boa, Chilabothrus angulifer (Boidae)

The Cuban Boa (Chilabothrus angulifer) is a top terrestrial predator in Cuba. References to prey species consumed by this boa date to when the first Europeans arrived in the region more than 500 years ago. However, long-term studies on its trophic ecology do not exist. The scarce and scattered records on its feeding habits indicate that this boa preys on a variety of native and domestic animals. Based on dietary information collected in the field and from the literature, we characterized the diet of this snake and tested four different hypotheses: (1) The Cuban Boa is a generalist predator; (2) the diets of boas in natural and anthropogenic habitats differ; (3) an ontogenetic shift in diet occurs; and (4) foraging strategies used in natural and anthropogenic habitats differ. We identified 49 prey species from 351 prey items obtained from 218 snakes, including 71 items (31 snakes) from the literature. Mammals represented 55% of total prey items consumed, followed by birds (41%) and ectotherms (4%). Chilabothrus angulifer exhibited a narrow niche breadth. However, rather than a trophic specialist, we consider this boa an opportunistic generalist predator, capable of adjusting its diet and foraging behavior according to prey availability and abundance. The diet of Ch. angulifer changed dramatically from mostly native mammals and birds in natural habitats to mostly livestock, pets, and human com­mensals in human-altered habitats. Also, mammals were consumed more frequently in natural habitats, whereas birds dominated the diet of boas associated with anthropogenic habitats. Few ectotherms were consumed in either type of habitat. We observed an ontogenetic shift in diet, but this primarily reflected a trend of consuming larger prey rather than a shift from ectotherms to endotherms as reported for some other boids. In natural habitats, Ch. angulifer used both ambush and active-foraging modes by day and night, whereas in anthropogenic situations, most boas used an active-foraging strategy at night. The frequent consumption of domestic animals by Cuban Boas might be the principal reason for the historical human-wildlife conflict involving this species in rural areas of Cuba.