Biology subjects

Kurze, C.

Publications and source records attributed to Kurze, C..

8 recordsLinked to original sources

bioRxiv2026

Sublethal effects of the organosilicone surfactant Silwet L-77 and its interactions with acetamiprid and sulfoxaflor on honeybee (Apis mellifera) sensory perception and cognition

Pesticides remain indispensable for global food security, yet their use must be reconciled with the preservation of biodiversity. Despite advances in developing "safer" pesticides, their sublethal effects and synergistic potential with co-formulants in tank-mixtures, including "inert" spray adjuvants, often remain poorly understood in beneficial insects like bees. In this study, we assessed the effects of acute oral exposure to both single compounds and adjuvant-insecticide mixtures on gustatory responsiveness, associative olfactory learning, and 90-minute short-term memory retention in honeybee foragers (Apis mellifera L.). Specifically, individual foragers were exposed to either single compounds (0.1%, 0.5%, 1% or 2.5% SilwetTM L-77; 6, 30 or 150 ng acetamiprid; 3, 9 or 27 ng sulfoxaflor), adjuvant-insecticide mixtures (0.5% or 1% SilwetTM L-77 combined with 6 or 30 ng acetamiprid, or 3 or 9 ng sulfoxaflor), a positive control (6 ng imidacloprid), or negative controls (0%, 0.1%, and 1% acetone). While we found no significant interaction effects for these adjuvant-insecticide mixtures, single-compound exposure to the highest doses of 2.5% SilwetTM L-77 and 27 ng sulfoxaflor significantly reduced gustatory responsiveness. Furthermore, all three agrochemicals alone weakly affected associative learning without impacting short-term memory retention. Although adjuvant-insecticide mixtures did not significantly impair learning ability, these adjuvants may impact sensory perception. Moving beyond mortality-based assessments and including behavioural assay to test sensory perception and learning ability is essential for gaining a more holistic understanding of pollinator health.

animal behavior and cognition↗

bioRxiv2026

Age-dependent shift from high lipid reserves to high haemolymph sugar supply underlies worker maturation in Bombus terrestris (Hymenoptera: Apidae)

Division of labour is key to the success of eusocial insects, including ants, termites, social wasps, and bees. While the well-studied honeybees are the primary example of age-based polyethism, the physiological transitions and underlying mechanisms mediating task allocation remain poorly understood in its sister taxon, the bumblebees. To gain a better understanding of the energy homeostasis in bumblebees carrying out different tasks, we quantified the haemolymph sugar titres (fructose, glucose, and trehalose) and lipid reserves across five age classes (0-28 days) and varying body sizes in Bombus terrestris (Hymenoptera: Apidae). Our results reveal novel insights into the physiological maturation of bumblebees, characterised by a drastic metabolic shift during the first week of adult life. While newly emerged workers ([≤] 1 day) show high lipid reserves and low circulating sugar levels, by the age of 7 days, lipid reserves are depleted by half, while circulating glucose and trehalose levels increase 4-to 6-fold and remain relatively stable thereafter. Although body size (i.e. dry mass) positively correlated with absolute lipid content in young workers and with trehalose in 14- and 21-day-old workers, age was the primary variable explaining the variation in our data. Our findings provide a mechanistic basis for age-based polyethism in bumblebees and highlight the importance of considering age as a fundamental factor in social insect research.

physiology↗

bioRxiv2025

Deferred mortality: cyclic thermal stress during pupation triggers irreversible carry-over costs in a key pollinator

Extreme heatwaves threaten global biodiversity, yet the sublethal carry-over effects of developmental thermal stress on adult fitness remain poorly understood. We addressed this knowledge gap for bumblebees, key pollinators that face alarming population declines, using a controlled in vitro approach. We exposed Bombus terrestris pupae to cyclic thermal stress to evaluate emergence success, adult longevity, and morphological traits. Cyclic thermal stress caused significant acute pupal mortality (up to 30% reduced emergence) and, crucially, deferred mortality, significantly reducing adult longevity (hazard ratio, HR = 2.00) in both workers and males. Rearing in vitro at 34{degrees}C showed no significant difference compared to individuals that developed naturally in their natal colony (HR = 0.95). Antennal and wing deformations served as powerful hazard indicators (HR = 2.38) for premature adult mortality. Our findings reveal that cyclic thermal stress during pupal development imposes irreversible developmental damage, undermining adult physiological resilience.

ecology↗

bioRxiv2025

Heatwave length and severity drive development disruption in a key pollinator

The increasing frequency and intensity of extreme thermal events like heatwaves, driven by climate change, threaten global biodiversity and entire ecosystems. Despite alarming projections of population declines for key pollinators like bumblebees, little is known about the direct impact of varying elevated temperatures during their pupal development. To gain a better understanding of the dose-response to thermal stress, we experimentally exposed Bombus terrestris L. (Hymenoptera: Apidae) pupae in vitro to varying thermal stress lengths (3-7 days) and intensities (36-38{degrees}C). This mechanistic approach allowed us to uniquely isolate the direct physiological effects of temperature on pupal development from complex colony dynamics and assess individual emergence success, developmental duration, body size, relative lipid content, and wing geometrics morphometrics. At the critical threshold of 38{degrees}C, pupal emergence was drastically reduced (2-5 fold) and wing deformities increased (4-7 fold). Even excluding wing deformities, we found thermal stress-induced effects on emerged worker wing shape and directional asymmetry. Hence, our findings suggest that increased extreme thermal stress negatively impacts bumblebee pupal development. Given the relative heat tolerance of B. terrestris, we expect even greater vulnerability in more cold-adapted bumblebee species.

ecology↗

bioRxiv2024

Experimental short-term heatwaves negatively impact body weight gain and survival during larval development in a wild pollinator

Climate change-induced heatwaves threaten global biodiversity, including crucial pollinators like bumblebees. Despite alarming projections, little is known about the effects of short-term heatwaves on insect larval development. Hence, we investigated the impact of simulated heatwaves on the development of fourth instar larvae (L4) of Bombus terrestris L. (Hymenoptera: Apidae) using an in vitro rearing method. Individual larvae were incubated at 37{degrees}C and 38{degrees}C for a period of 4 days, with a constant rearing temperature of 34{degrees}C as the control. We examined body weight gain, developmental duration, survival to adult stage, and adult body size (i.e. dry mass, ITD, and head width). A simulated heatwave of 37{degrees}C did not significantly affect larval development, but 38{degrees}C impaired larval body mass gain. While developmental duration and adult body size were unaffected, an acute heat stress of 38{degrees}C during the L4 stage reduced the probability of pupae reaching adulthood. These findings highlight the potential for heatwaves to negatively affect bee populations by impairing larval growth and reducing survival to the adult stage, which may have severe implication for colony fitness.

developmental biology↗

bioRxiv2024

Age, not body size, influences flight distance in the bumble bee Bombus terrestris L. (Hymenoptera: Apidae)

Bumble bees and honey bees provide crucial pollination service and have become important insect model system. Despite their close relation, they differ in their morphology, physiology, and social organisation. Notably, honey bees workers exhibit age-based polyethism, while bumble bees display considerable body size variation. Though body size is known to affect foraging range, behaviour, and flight ability, the influence of age remains less explored. Here we studied the flight performance (distance and speed) in aging bumble bee workers using tethered flight mills. Additionally, we measured their intertegular distance (ITD), dry mass, and fat content. Flight distance was predominantly influenced by age, challenging assumptions that age does not play a role in foraging and task allocation. Between 7 to 14 days, flight distance increased six-fold before a slight decline at the age of 21 days, aligning with age-dependent flight physiology in honey bees. Larger workers had decreasing mass-specific fat reserves, challenging the notion about their energy preservation for oocyte development. Our findings indicate that age substantially influences flight distance, impacting foraging performance and potentially altering task allocation strategies. This underscores the need to consider individual age and physiological changes alongside body size and mass in experiments involving bumble bee workers.

physiology↗

bioRxiv2024

High variability in the attractiveness of municipally-planted decorative plants to pollinators

Insect populations are declining globally. A major driver of this decline is land use change, including urbanisation. However, urban environments can also offer a wide range of floral resources to pollinators, through ornamental plantings, but these can vary widely in their attractiveness to insects. Often, the largest single planter of ornamental plants in an urban area is the municipality. Here we evaluated the decorative plantings carried out by the city municipality of Regensburg, Germany, by systematically surveying insect visitations on different plant types in late summer, when forage is often limited for pollinators. We found a 130-fold increase from the least to the most attractive plants, and high variation in which insect groups were attracted to which plants. While honey bees, which are not conservation concern, were the most common insect visitors, some decorative plants attracted a very large proportion of wild bees, flies, and wasps. Our results demonstrate that there is great scope for increasing the supply of urban forage to pollinators in general, and specific groups in particular, without requiring new decorative plant types to be sourced or planted. We argue that providing local evidence-based guidance to municipalities offers a quick and potentially cost-neutral method for supporting urban insect populations.

ecology↗

bioRxiv2018

Computer vision and deep learning automates nocturnal rainforest ant tracking to provide insight into behavior and disease risk

Determining how ant colonies optimize foraging while mitigating disease risk provides insight into how the ants have achieved ecological success. Fungal infected cadavers surround the main foraging trails of the carpenter ant Camponotus rufipes, offering a system to study how foragers behave given the persistent occurrence of disease threats. Studies on social insect foraging behavior typically require many hours of human labor due to the high density of individuals. To overcome this, we developed deep learning based computer vision algorithms to track foraging ants, frame-by-frame, from video footage. We found foragers can be divided into behavioral categories based on how straight they walk across the trail. Eighty percent of ants walk directly across the trail, while 20% wander or circle when crossing the trail. Departure from the main trail encourages exploration of new areas and could enhance discovery of new food resources. Conversely, results from our agent-based model simulations suggest deviation from a straight path exposes foragers to more infectious fungal spores. Consistency in walking behavior may protect most ants from infection, while the foragers with increased exposure due to their mode of walking could be a sufficient number of new hosts to sustain disease in this environment.

animal behavior and cognition↗