Over the years, our lab explored a range of research questions that shaped our current perspective on behavior, life-history, and decision-making. Below are a few examples of past research directions.
Past Research 1:
Wormlions as a model for habitat choice, ecological trade-offs, and urban adaptation
In a series of studies, our lab used wormlions, pit-building fly larvae, as a model system to examine habitat choice, ecological trade-offs, and adaptation to urban environments. Wormlions construct sand pits to capture prey, convergently evolving a hunting strategy strikingly similar to that of unrelated pit-building antlions. This system allowed us to explore questions of convergent evolution, competition between ecologically similar predators, and the ecological constraints shaping trap-building behavior.
We showed that wormlions strongly prefer shaded and covered microhabitats, but that this preference is context-dependent. When habitat quality is reduced (for instance, by shallow or obstructed sand), habitat preferences weaken, whereas increasing temperatures strengthen the preference for shade. These results highlight how environmental conditions modulate decision-making under physiological stress.
Our work further demonstrated that urban environments can provide high-quality habitats for wormlions. Cities offer fine-grained sand that enables the construction of larger pits, high prey availability in the form of small ants, and structural elements such as walls that provide shade and influence prey movement. Together, these studies illustrate how small-scale habitat features and ecological trade-offs shape behavior, performance, and success in human-modified environments.
Selected publications:
Bar-Ziv et al. (2018) Zoology
Scharf et al. (2021) Biology
Miler & Scharf (2022) Behavioral Ecology & Sociobiology
Past Research 1:
Wormlions as a model for habitat choice, ecological trade-offs, and urban adaptation
In a series of studies, our lab used wormlions, pit-building fly larvae, as a model system to examine habitat choice, ecological trade-offs, and adaptation to urban environments. Wormlions construct sand pits to capture prey, convergently evolving a hunting strategy strikingly similar to that of unrelated pit-building antlions. This system allowed us to explore questions of convergent evolution, competition between ecologically similar predators, and the ecological constraints shaping trap-building behavior.
We showed that wormlions strongly prefer shaded and covered microhabitats, but that this preference is context-dependent. When habitat quality is reduced (for instance, by shallow or obstructed sand), habitat preferences weaken, whereas increasing temperatures strengthen the preference for shade. These results highlight how environmental conditions modulate decision-making under physiological stress.
Our work further demonstrated that urban environments can provide high-quality habitats for wormlions. Cities offer fine-grained sand that enables the construction of larger pits, high prey availability in the form of small ants, and structural elements such as walls that provide shade and influence prey movement. Together, these studies illustrate how small-scale habitat features and ecological trade-offs shape behavior, performance, and success in human-modified environments.
Selected publications:
Bar-Ziv et al. (2018) Zoology
Scharf et al. (2021) Biology
Miler & Scharf (2022) Behavioral Ecology & Sociobiology
(A) The music academy at Tel Aviv University.
(B) Wormlions pits are abundant below the shade of the
building.
(C) Two wormlions were pulled out of their pits and
photographed next to a 2 Euro coin.
(B) Wormlions pits are abundant below the shade of the
building.
(C) Two wormlions were pulled out of their pits and
photographed next to a 2 Euro coin.
A small garden next to the Central Library at Tel Aviv University, where wormlions are abundant.
Past research 2:
Stress, thermal variation, and starvation in insects
Stressors are common in nature, and animals rarely experience optimal conditions for extended periods. In a series of studies, our lab examined how insects cope with two major ecological stressors: temperature variation and starvation. Using the red flour beetle (Tribolium castaneum) as a model system, we explored how stress affects development, physiology, behavior, and life-history traits.
Our work showed that the effects of thermal stress depend strongly on context and timing. Short-term thermal acclimation can improve performance under stressful temperatures, whereas long-term developmental exposure does not necessarily confer the same benefits. We further demonstrated that repeated cold stress impairs reproductive and foraging-related behaviors, yet simultaneously increases fat reserves and starvation tolerance, suggesting a shift toward an energy-saving physiological state.
In addition, we found that starvation generally has negative effects on performance and thermal tolerance. However, recovery from starvation can be rapid, and alternating periods of food deprivation and feeding often mitigate these negative effects. Together, these studies revealed that moderate stress can sometimes enhance performance, and pointed to the conditions under which such beneficial effects emerge when organisms face multiple stressors simultaneously.
Selected publications:
Scharf et al. (2015) Evolutionary Biology
Scharf et al. (2016) Science of Nature
Scharf et al. (2019) Insect Science
Scharf et al. (2022) Journal of Thermal Biology
Stress, thermal variation, and starvation in insects
Stressors are common in nature, and animals rarely experience optimal conditions for extended periods. In a series of studies, our lab examined how insects cope with two major ecological stressors: temperature variation and starvation. Using the red flour beetle (Tribolium castaneum) as a model system, we explored how stress affects development, physiology, behavior, and life-history traits.
Our work showed that the effects of thermal stress depend strongly on context and timing. Short-term thermal acclimation can improve performance under stressful temperatures, whereas long-term developmental exposure does not necessarily confer the same benefits. We further demonstrated that repeated cold stress impairs reproductive and foraging-related behaviors, yet simultaneously increases fat reserves and starvation tolerance, suggesting a shift toward an energy-saving physiological state.
In addition, we found that starvation generally has negative effects on performance and thermal tolerance. However, recovery from starvation can be rapid, and alternating periods of food deprivation and feeding often mitigate these negative effects. Together, these studies revealed that moderate stress can sometimes enhance performance, and pointed to the conditions under which such beneficial effects emerge when organisms face multiple stressors simultaneously.
Selected publications:
Scharf et al. (2015) Evolutionary Biology
Scharf et al. (2016) Science of Nature
Scharf et al. (2019) Insect Science
Scharf et al. (2022) Journal of Thermal Biology
Past research 3:
Movement, shelter use, and spatial decision-making in flour beetles
In this project, we used the red flour beetle (Tribolium castaneum) as a model system to study how insects move through space, select shelters, and respond to fine-scale spatial features in their environment. We focused on how subtle properties such as corner geometry, obstacle structure, and substrate characteristics shape movement decisions and habitat use.
We showed that flour beetles do not treat all shelters equally: they spend more time in acute-angled corners than in right- or obtuse-angled ones, indicating sensitivity to corner geometry and a preference for locations offering greater perceived protection. Acute angles also altered movement paths and re-entry behavior, likely due to wall-following and the costs of sharp turns.
We further demonstrated that substrate properties and their spatial arrangement influence movement behavior. Beetles moved differently on smooth versus rough or loose substrates, with changes in movement distance, stopping behavior, and attraction to walls. Together, these studies highlight how movement behavior emerges from interactions between animals and the fine-scale structure of their environment, and emphasize the importance of carefully considering arena design in behavioral experiments.
Selected publications:
Scharf et al. (2023) Insect Science
Hanna & Scharf (2024) Insect Science
Hanna et al. (2025) Journal of Zoology
Movement, shelter use, and spatial decision-making in flour beetles
In this project, we used the red flour beetle (Tribolium castaneum) as a model system to study how insects move through space, select shelters, and respond to fine-scale spatial features in their environment. We focused on how subtle properties such as corner geometry, obstacle structure, and substrate characteristics shape movement decisions and habitat use.
We showed that flour beetles do not treat all shelters equally: they spend more time in acute-angled corners than in right- or obtuse-angled ones, indicating sensitivity to corner geometry and a preference for locations offering greater perceived protection. Acute angles also altered movement paths and re-entry behavior, likely due to wall-following and the costs of sharp turns.
We further demonstrated that substrate properties and their spatial arrangement influence movement behavior. Beetles moved differently on smooth versus rough or loose substrates, with changes in movement distance, stopping behavior, and attraction to walls. Together, these studies highlight how movement behavior emerges from interactions between animals and the fine-scale structure of their environment, and emphasize the importance of carefully considering arena design in behavioral experiments.
Selected publications:
Scharf et al. (2023) Insect Science
Hanna & Scharf (2024) Insect Science
Hanna et al. (2025) Journal of Zoology
