Eran Levin

Tel Aviv University | TAU · Department of Zoology

Marine iguanas occasionally face severe food shortages because of algal dieback during El Niño events. Research on their adaptations to these periods has highlighted their unique ability to shrink in body length, which reduces their energetic needs. Additional mechanisms, like sustaining lower body temperatures and metabolic rates, could potentiall...

Ethanol, a natural by-product of sugar fermentation, can be found in various fruits and nectar. Although many animals routinely consume ethanol in low concentrations as part of their natural diets, its inherent toxicity can cause severe damage. Even species particularly well adapted to ethanol consumption face detrimental effects when exposed to co...

Dietary fatty acids (FAs) are essential macronutrients affecting animal fitness, growth, and development. While the degree of saturation of FAs usually determines the level of absorption and allocation within the body, the utilization of dietary FAs across the life stages of individuals remains unknown. We used three different 13 C labeled FAs, wit...

Aim: Squamate fitness is affected by body temperature, which in turn is influenced by environmental temperatures and, in many species, by exposure to solar radiation. The biophysical drivers of body temperature have been widely studied, but we lack an integrative synthesis of actual body temperatures experienced in the field, and their relationship...

Social wasps exhibit a unique nutritional cycle in which adults feed larvae with prey, and larvae provide adults with larval secretions (LS). LS serves as a vital nutritional source for adults, contributing to the colony’s health and reproductive success. The LS nutrient composition has been previously reported in various wasp species, yet these an...

In winter, many reptiles have a period of inactivity (“brumation”). During brumation there is no energetic intake, therefore there would be an advantage to reducing energetic expenditure. The size of energetically costly organs, a major determinant of metabolic rate, is known to be flexible in many tetrapods. Seasonal plasticity of organ size could...

Populations inhabiting several biomes may experience different abiotic and biotic conditions, exerting local selection pressures. Temperature and water regimes are interconnected variables, that may differ between biomes, and greatly influence ecophysiological traits, such as metabolic and evaporative water loss rates. We hypothesized that Ptyodact...

Dietary fatty acids (FAs) have been demonstrated to be differentially stored or used as a metabolic fuel, depending on carbon chain length or saturation level. However, intestinal absorption also differs among FAs, potentially biasing conclusions on functional differences and their subsequent implications. We tested dietary FA usage by a nocturnal...

The gut microbiota is intimately related to host wellbeing, in terms of physiology, immune function, and even social interactions. The strength of this relationship is dynamic, but the extent to which the microbiome is shaped by the identity of the host (nature) or its environment (nurture) remains largely unknown. Here we aimed to identify factors...

The reptilian form of hibernation (brumation) is much less studied than its mammalian and insect equivalents. Hibernation and brumation share some basic features but may differ in others. Evidence for hypometabolism in brumating reptiles beyond the effect of temperature is sporadic and often ignored. We calculated the standard metabolic rates (SMR,...

Pollen serves as a crucial source of protein and lipids for numerous insects. Despite the importance of pollen lipids for nutrient regulation in bees, the digestibility and absorption of different fatty acids (FAs) by bees remain poorly understood. We used 13C labeled fatty acids (FAs) to investigate the absorption and allocation of three common di...

The scaling of the energetic cost of locomotion with body mass is well documented at the interspecific level. However, methodological restrictions limit our understanding of the scaling of flight metabolic rate (MR) in free-flying insects. This is particularly true at the intraspecific level, where variation in body mass and flight en-ergetics may...

Camouflage is a common trait enabling animals to avoid detection by predators and prey. Patterns such as spots and stripes are convergent across carnivore families, including felids, and are hypothesized to have adaptive value through camouflage. House cats (Felis catus) were domesticated thousands of years ago, but despite artificial selection for...

Social insects employ a variety of active and passive mechanisms for nest thermoregulation. Many social wasp species exhibit a particular nest-architecture by building their nests with cells facing downward. By using thermal imaging to characterize the heat diffusion throughout Oriental hornet nests from different angular positions, we show that th...

During a series of explosions in a recent eruption of violence between Israel and Gaza, the metabolic rate of a Syrian Blind Snake Xerotyphlops syriacus peaked acutely, and its breathing pattern changed. This is the first record of a wild animal’s real-time physiological response to the noise of an incoming rocket attack and highlights the gap in o...

Urban environments offer dramatically different habitats for wildlife compared with natural environments. They provide, for example, different levels of resource availability, anthropogenic night light, and microclimates (e.g., urban heat islands). For reptiles, increased temperatures in the city can lead to increased energetic demands and metaboli...

Nutritional exchanges play a fundamental role in the evolution of animal societies. In higher animal societies, while adult individuals can be both food donors and receivers, the offspring usually only receive food from the adults. Hornets and wasps are fierce insect hunters that feed their larvae with prey. However, although the adults also consum...

Carbon dioxide (CO2) has pleiotropic effects on insect physiology and behavior. Although diverse, many impacts are related to changes in metabolism and reallocation of macronutrients. Here we examined the metabolic shift induced by CO2 and its regulation using Bombus impatiens. CO2 applied to bumble bee gynes induces bypass of diapause and transiti...

Temperature and precipitation are major components of climate that have a pervasive effect on the phenotype and physiology of insects. The Oriental hornet has a wide geographical distribution and is the only vespid species found in a desert environment. Recently, it has extended its geographic distribution due to climate change and human activities...

A lecture i gave in a conference regarding part of my master's research work

Sexual dimorphisms are responsible for profound metabolic differences in health and behavior. Whether males and females react differently to environmental cues, such as solar ultraviolet (UV) exposure, is unknown. Here we show that solar exposure induces food-seeking behavior, food intake, and food-seeking behavior and food intake in men, but not i...

Adult wasps primary food resource is larval saliva. This liquid secretion consists mainly of amino acids and carbohydrates processed from the prey brought to the colony by the foragers. However, adults also regularly consume floral nectar. The nectar's most abundant proteinogenic amino acid is proline, and the two most abundant non-proteinogenic am...

Males of social Hymenoptera spend the first days following eclosion inside the nest before dispersing to find a young queen to mate with. During this period, they must acquire enough nutrients to enable their sexual maturation and store energy to sustain them through their nuptial journey. It was previously argued that adult hornets are unable to p...

Rose chafer beetles (Protetia cuprea) are pollinators as well as agricultural pests, flying between flowers and trees while foraging for pollen and fruits. Calculating the energy they expend on flying during foraging activity faces the challenge of measuring the metabolic rate (MR) of free‐flying insects in an open space. We overcame this challenge...

Juvenile hormone (JH) is a modulator of many physiological transitions in insects, including molting, metamorphosis, diapause, and reproduction. These processes often include metabolic changes. Here we show that JH accelerates metabolic rate in bumble bees (Bombus terrestris). We reduced JH levels in worker bumble bees by removing their corpora all...

Fatty acids (FA) are the primary metabolic fuel for many organisms and the fundamental component of membranes of all living organisms. FAs can be saturated (SFA), monounsaturated (MUFA), or polyunsaturated (PUFA). PUFA are not synthesized by most animals and are considered as essential nutrients. We examined the effect of climate on the saturation...

Oriental hornet (Vespa orientalis) foragers are strong, long-distance flyers exhibiting a high metabolic rate. Accordingly, they feed on carbohydrate-rich diets, such as floral nectar and larval secretions. These nutritional sources, in addition to carbohydrates, also contain free amino acids (AAs). Leucine, glycine, and proline are three common AA...

Aim Patterns of separation among males and females, known as sexual segregation, are traditionally correlated with elevation or latitude in animals. Alternatively, in humans, spatial and behavioural segregation is driven by inherent sex-based differences in thermal preference, although the cause and adaptive value of these differences remain unclea...

Measuring metabolic rate (MR) poses a formidable challenge in free-flying insects who cannot breathe into masks or be trained to fly in controlled settings. Consequently, flight MR has been predominantly measured on hovering or tethered insects flying in closed systems. Stable isotopes such as labelled water allow measurement of MR in free-flying a...

The main challenge facing a parasite of social insects lies in deceiving its host’s detection and defense systems in order to enter and survive within the host colony. Sphecophaga orientalis is an ichneumonid wasp that parasitizes the pupae of the Oriental hornet Vespa orientalis. In Israel’s Mediterranean region, this parasitoid infects on average...

Aim There is an increasing evidence showing that species within various taxonomic groups have reticulate evolutionary histories with several cases of introgression events. Investigating the phylogeography of species complexes can provide insight into these introgressions, and when and where these hybridizations occurred. In this study, we investiga...

Aim There is increasing evidence showing that species within various taxonomic groups have reticulate evolutionary histories with several cases of introgression events. Investigating the phylogeography of species complexes can provide insight about the introgressions, when and where these hybridizations occurred. In this study, we investigate the b...

Behaviour is an important way for animals to rapidly respond to changes in their current environment; however, over extended periods animals can also respond to environmental change via slower, developmental plasticity in other traits. This developmental plasticity could itself alter the animal's behaviour in two ways: it could change the state of...

Poster presented at the 54th convention of the Zoological Society of Israel

The different reproductive strategies of males and females underlie differences in behavior that may also lead to differences in nutrient use between the two sexes. We study sex differences in the utilization of two essential amino acids (EAAs) and one non-essential amino-acid (NEAA) by the Carolina sphinx moth (Manduca sexta). On day one post-eclo...

The different reproductive strategies of males and females have selected for differences in function and behavior that may translate into differences in resource use. Here we studied sexual differences in the utilization of essential and non‐essential amino acids by the Carolina sphinx moth ( Manduca sexta: Sphingidae ). We labeled two essential am...

Sugar rush Flying requires high levels of energy production, which causes muscular oxidative damage. Food-derived antioxidants can protect against such damage; however, nectar is devoid of these compounds. Levin et al. found that nectar-feeding hawkmoths fed high concentrations of sugar had lower levels of damage than unfed moths. Sugar-fed moths g...

The ability to allocate resources, even when limited, is essential for survival and fitness. We examine how nutrients that occur in minute amounts are allocated among reproductive, somatic and metabolic demands. In addition to sugar, flower nectars contain two macronutrients—amino acids and fatty acids. We created artificial nectars spiked with 13...

Direct benefits provided by males have large effects on the fitness of females and their offspring in many species. Here, we examined whether mating or feeding experience of male Carolina sphinx moths, Manduca sexta (Sphingidae), affects the quality of direct benefits that males provide to their mates. We mated virgin females with fed and unfed, vi...

We report that two species of mouse-tailed bats (Rhinopoma microphyllum and R. cystops) hibernate for five months during winter in geothermally heated caves with stable high temperature (20°C). While hibernating, these bats do not feed or drink, even on warm nights when other bat species are active. We used thermo-sensitive transmitters to measure...

Animals often deal with situations in which vast sensory input is received simultaneously. They therefore must possess sophisticated mechanisms to select important input and ignore the rest. In bat echolocation, this problem is at its extreme. Echolocating bats emit sound signals and analyse the returning echoes to sense their environment. Bats fro...

Social foraging is a very common yet extremely complex behavior [1]. Numerous studies attempted to model it [2-7] with little supporting evidence. Studying it in the wild is difficult because it requires monitoring the animal's movement, its foraging success, and its interactions with conspecifics. We present a novel system that enables full night...

Competition has long been assumed to be a major driver in regulating ecological communities. Intra-specific competition is considered to be maximal as members of the same species use the same ecological niches in a similar way. Many species of animals exhibit great physiological, behavioral, and morphological differences between sexes (sexual dimor...

Number of tracking nights and positions taken for 38 bats during 2007–2008. (DOC)

Results of GWR models for the spatial dispersal of male and female bats in the first hour of foraging and afterwards. (DOC)

We used radio-telemetry, observations and physiological measurements to study the basic biology and energetic strategies of Asellia tridens in northern Israel from 2009 to 2010. Between late May and early November, the bats occupied abandoned man-made structures in this area. Parturition occurred between late June and mid-July, and juveniles were i...

Prior to hibernation, mammals accumulate large amounts of fat in their bodies. In temperate mammalian species, hibernation is improved by increasing the levels of poly-unsaturated fatty acids (PUFA) in the body. The saturation of fatty acids (FA) in both white adipose tissue (WAT) and membrane phospholipids of mammals often reflects their diet comp...

During the past few years it has become clear that torpor and hibernation are not limited to high latitudes or cold climates. We studied summer roost selection and torpor patterns of a subtropical greater mouse-tailed bat, Rhinopoma microphyllum, on the edge of its distribution range. During summer, these bats exhibited complete sexual segregation,...

A comprehensive survey as a means to finding cryptic species.

Partial results of M.Sc. about the biology of Asellia tridens.

Bats (classified in the order Chiroptera) are the most abundant and widely distributed species of mammals in the world. They occupy a variety of ecosystems and are known for their ecological importance as seed dispersers, pollinators and insectivores. The order Chiroptera, containing 33 known species, is the largest mammalian order in Israel Bats a...

The NAD+-dependent SIRT6 deacetylase is a therapeutic candidate against the emerging metabolic syndrome epidemic. SIRT6, whose deficiency in mice results in premature aging phenotypes and metabolic defects, was implicated in a calorie restriction response that showed an opposite set of phenotypes from the metabolic syndrome. To explore the role of...

In many ant species, nuptial flight tends to be short in time and assumed to be synchronous across a large area. Here, we report that, in the upper Jordan Valley, northern Israel, massive nuptial flights of Carpenter ants (Camponotus sp.) occur frequently throughout the summer, and their alates form up to 90% of the diet of the greater mouse-tailed...

The greater mouse-tailed bat (Rhinopoma microphyllum) possesses a large geographical range, covering most of the arid and warm areas of the Old World. We studied the genetic variability of this species using two mitochondrial markers (the cytochrome b gene and the control region), from several Israeli colonies and from over most of the species' ran...

During the winter of 2003–2004 feces were collected from a winter colony of the long-fingered bat (Myotis capaccinii) in the Hazorea cave (north-west Israel). Of the 1913 feces that were examined, 234 contained scales of Gambusia affinis – a small fish that had been introduced to Israel around 1920 in order to control mosquito larvae. The remains o...