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[...]cleaners acquire food and clients are freed from unwanted organisms and material. In one of the events, a group of six pufferfish lingered and posed horizontally in a slightly head-up position near the surface at a cleaning station with no cleaner visible and no other potential client present at this moment (Fig. 1). At another station with no other potential client present, I observed a group of seven pufferfish posing and being inspected and cleaned by the batfish (Fig. 3). Declarations Conflict of interest The author declared that he has no conflict of interest.

The reduction of predation is a potentially important factor for the evolution of the traits of an island animal species. By relaxed selection, insular animals tend to lose their antipredator behaviors. A monophyletic group of pitvipers (genus Bothrops ) in southeastern Brazil, which have high genetic affinity and dwell on the mainland and adjacent islands, provide an appropriate setting to study the evolution of antipredator behavior and how different predatory stimuli can influence this behavior. The mainland Bothrops jararaca has several terrestrial and aerial predators, whereas B . insularis and B . alcatraz , restricted to two small islands, Queimada Grande and Alcatrazes, respectively, have a smaller range of aerial predators. Terrestrial predators are absent on Queimada Grande, but one potential snake predator occurs on Alcatrazes. We observed that the defensive repertoire of island snakes has not been lost, but they display different frequencies of some antipredator behaviors. The type of predatory stimuli (terrestrial and aerial) influenced the defensive response. Bothrops insularis most often used the escape strategies, especially against terrestrial predatory stimuli. Bothrops alcatraz displayed the highest rate of strike for both terrestrial and aerial stimuli. Our results indicate that even though relaxed selection may occur in island environments as compared to mainland environments, these pitvipers still retain their antipredator behaviors but with different response degrees to the two predator types.

Snakebites affect millions of people worldwide. The majority of research and management about snakebites focus on venom and antivenom, with less attention given to snake ecology. The fundamental factor in snakebites is the snakes’ defensive biting behavior. Herein we examine the effects of environmental variables (temperature, time of day, and human stimulus) and biological variables (sex and body size) on the biting behavior of a medically significant pit viper species in Brazil, Bothrops jararaca (Viperidae), and associate it with the epidemiology of snakebites. Through experimental simulations of encounters between humans and snakes, we obtained behavioral models applicable to epidemiological situations in the State of São Paulo, Brazil. We found a significant overlap between behavioral, morphological, environmental, and epidemiological data. Variables that increase snakebites in epidemiological data also enhance the tendency of snakes to bite defensively, resulting in snakebites. We propose that snakebite incidents are influenced by environmental and morphological factors, affecting the behavior of snakes and the proportion of incidents. Thus, investigating behavior of snakes related to snakebite incidents is a valuable tool for a better understanding of the epidemiology of these events, helping the prediction and, thus, prevention of snakebites.

Large-scale geographical patterns of biotic specialization and the underlying drivers are poorly understood, but it is widely believed that climate plays an important role in determining specialization. As climate-driven range dynamics should diminish local adaptations and favor generalization, one hypothesis is that contemporary biotic specialization is determined by the degree of past climatic instability, primarily Quaternary climate-change velocity. Other prominent hypotheses predict that either contemporary climate or species richness affect biotic specialization. To gain insight into geographical patterns of contemporary biotic specialization and its drivers, we use network analysis to determine the degree of specialization in plant-hummingbird mutualistic networks sampled at 31 localities, spanning a wide range of climate regimes across the Americas. We found greater biotic specialization at lower latitudes, with latitude explaining 20-22% of the spatial variation in plant-hummingbird specialization. Potential drivers of specialization--contemporary climate, Quaternary climate-change velocity, and species richness--had superior explanatory power, together explaining 53-64% of the variation in specialization. Notably, our data provides empirical evidence for the hypothesized roles of species richness, contemporary precipitation and Quaternary climate-change velocity as key predictors of biotic specialization, whereas contemporary temperature and seasonality seem unimportant in determining specialization. These results suggest that both ecological and evolutionary processes at Quaternary time scales can be important in driving large-scale geographical patterns of contemporary biotic specialization, at least for co-evolved systems such as plant-hummingbird networks.

Despite a strong increase in research on seamounts and oceanic islands ecology and biogeography, many basic aspects of their biodiversity are still unknown. In the southwestern Atlantic, the Vitória-Trindade Seamount Chain (VTC) extends ca. 1,200 km offshore the Brazilian continental shelf, from the Vitória seamount to the oceanic islands of Trindade and Martin Vaz. For a long time, most of the biological information available regarded its islands. Our study presents and analyzes an extensive database on the VTC fish biodiversity, built on data compiled from literature and recent scientific expeditions that assessed both shallow to mesophotic environments. A total of 273 species were recorded, 211 of which occur on seamounts and 173 at the islands. New records for seamounts or islands include 191 reef fish species and 64 depth range extensions. The structure of fish assemblages was similar between islands and seamounts, not differing in species geographic distribution, trophic composition, or spawning strategies. Main differences were related to endemism, higher at the islands, and to the number of endangered species, higher at the seamounts. Since unregulated fishing activities are common in the region, and mining activities are expected to drastically increase in the near future (carbonates on seamount summits and metals on slopes), this unique biodiversity needs urgent attention and management.

Changing environmental conditions (water transparency, weather, and tide) in the estuarine bay allowed me to carry out 27 above surface observational sessions of 2–26 min (totalling 304 min) distributed over 24 days from 17 December 2021 to 14 May 2022 during daily walking on the embankment (see Sazima 2021). The proportion of diseased individuals varied from 3.3 to 15% in 11 groups of eight to 43 mullets at or near cleaning stations. [See PDF for image] Fig. 1 A possible pathway to spread pathogens between fishes: a juvenile silver trevally Pseudocaranx dentex closely associated to a sand mullet Myxus elongatus with skin lesions at an urban estuary in Australia [See PDF for image] Fig. 2 A possible increase of the chance to spread pathogens between fishes: a juvenile silver trevally Pseudocaranx dentex mingles with a mullet school cleaned by the silver batfish Monodactylus argenteus at an urban estuary in Australia. Escorting is recorded for juvenile trevallies and other jack species for various causes including food acquisition, chafing surface, and protection from predators (see references above and Inagaki et al. 2020). [...]chafing against animals receives more attention, possibly due to the eye-catching nature of the living substrate: sharks, manta rays, and sea turtles (Papastamatiou et al. 2007; Grossman et al. 2009; Krajewski et al. 2017; Nicholson-Jack et al. 2021; Williams et al. 2022). Fish species such as luderick, white trevally, sand mullet, and silver batfish, which dwell in estuaries or freshwater as a nursery habitat and latter move to marine or more open habitats or vice versa (Kuiter 2016), have the potential to carry parasites from one habitat to the other (Gillanders et al. 2003). [...]disease transmission in brackish water of the estuary may be a way to spread pathogens between freshwater and marine habitats, as some parasite types are able to undergo transitions between freshwater and marine environments (Okamura et al. 2022).

Fluorescence in amphibians and reptiles has emerged as a prominent study subject in recent years, with research focused on understanding its function and diversity. As the knowledge of fluorescence in vertebrates is still understudied, we surveyed amphibian and reptile species in montane and lowland Atlantic Forest sites to evaluate presence or absence of fluorescence. By randomly sampling species, we found evidence of fluorescence in amphibians of the genera Scinax, Brachycephalus and Hylodes, and reptiles of the genera Bothrops, Enyalius and Hemidactylus. Our findings increase the list of known species that may benefit from fluorescent patterns. Fluorescence was either ocular, dermal, or subdermal related to the skeleton or ossified dermal structures. Whether these species are able to see and interpret the different the patterns generated by fluorescent structures is yet to be discovered.

The glossophagine Pallas’s long-tongued bat (Glossophaga soricina) fares well in urban environments across its range. In addition to roost sites, there are nectar and fruit sources available in diverse situations across the urban gradient. Phyllostomid bats that thrive in urbanized situations are behaviorally plastic generalists and rely on patches of ornamental or feral plants as food sources. Herein we report on G. soricina and its food sources at an urbanized site in Southeastern Brazil. This small phyllostomid bat consumes nectar from landscaping ornamental plants, besides consuming the soft pulp along with the tiny seeds of pioneer trees and shrubs. In addition to these natural sources, the bat exploits hummingbird feeders to consume the sugared water. Ingested small seeds are defecated in flight, the bat acting as a disperser of pioneer plants that favor cleared areas. Glossophaga soricina role as flower-pollinator and seed-disperser at Neotropical urban areas merits further attention due both to the maintenance of urban biodiversity and delivery of ecosystem services. Resumo: O morcego beija-flor (Glossophaga soricina) adapta-se a ambientes urbanos na sua área de distribuição. Além de abrigos diurnos, há fontes de néctar e frutos ao longo do gradiente urbano. Morcegos filostomídeos que se adaptam a situações urbanas são generalistas comportamentalmente flexíveis e dependem de trechos com plantas ornamentais ou ferais como fonte alimentar. Relatamos aqui informações sobre o morcego beija-flor e suas fontes alimentares em um local urbanizado no sudeste do Brasil. Este pequeno morcego glossofagíneo busca néctar em plantas usadas em paisagismo, além de consumir a polpa macia, juntamente com as sementes minúsculas, de plantas pioneiras. Além destas fontes naturais, o morcego explora água açucarada dos bebedouros de beija-flores. Sementes pequenas são defecadas em voo e o morcego age como dispersor de plantas poineiras em áreas sem vegetação. A função de G. soricina como polinizador de flores e dispersor de sementes em áreas urbanas nos Neotrópicos merece atenção adicional devido à manutenção da biodiversidade urbana e da prestação de serviços ecossistêmicos.

Birds that remove ectoparasites and other food material from their hosts are iconic illustrations of mutualistic—commensalistic cleaning associations. To assess the complex pattern of food resource use embedded in cleaning interactions of an assemblage of birds and their herbivorous mammal hosts in open habitats in Brazil, we used a network approach that characterized their patterns of association. Cleaning interactions showed a distinctly nested pattern, related to the number of interactions of cleaners and hosts and to the range of food types that each host species provided. Hosts that provided a wide range of food types (flies, ticks, tissue and blood, and organic debris) were attended by more species of cleaners and formed the core of the web. On the other hand, core cleaner species did not exploit the full range of available food resources, but used a variety of host species to exploit these resources instead. The structure that we found indicates that cleaners rely on cleaning interactions to obtain food types that would not be available otherwise (e.g., blood-engorged ticks or horseflies, wounded tissue). Additionally, a nested organization for the cleaner bird—mammalian herbivore association means that both generalist and selective species take part in the interactions and that partners of selective species form an ordered subset of the partners of generalist species. The availability of predictable protein-rich food sources for birds provided by cleaning interactions may lead to an evolutionary pathway favoring their increased use by birds that forage opportunistically.