Issues
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Cover image
Cover Image
Cover: Hummingbirds can lower their body temperature and metabolism at night to save energy, using a strategy called torpor. Shankar et al. (jeb243208) found much finer control of hummingbird body temperature than birds are usually shown to have: they lower their temperature by varying amounts, and use a shallow form of torpor to balance the trade-offs of using deep torpor versus remaining in normal body temperature sleep. This composite thermal image shows a male black-chinned hummingbird in normal sleep early in the night (left), transitioning to deep torpor, and then in deep torpor (right). Photo credit: Anusha Shankar, Isabelle Cisneros and Don Powers.
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INSIDE JEB
NEWS
COMMENTARY
On the feeding biomechanics of nectarivorous birds
Summary: Nectar-feeding birds employ unique mechanisms to collect minute liquid rewards from floral structures. This Commentary details the three stages of nectar feeding and suggests research pathways to expand our current knowledge.
SHORT COMMUNICATION
Long distance homing in the cane toad (Rhinella marina) in its native range
Summary: Translocation-homing experiments reveal that non-territorial, non-migratory Rhinella marina can navigate to home areas following displacements exceeding regular, natural movements, suggesting a previously unconsidered prevalence of navigational abilities amongst amphibians.
RESEARCH ARTICLES
A novel intramandibular joint facilitates feeding versatility in the sixbar distichodus
Summary: The sixbar distichodus is a freshwater, plant-eating fish with an extra joint in its lower jaw that allows it to feed in new ways compared with fishes lacking the joint.
Discontinuous gas exchange in Madagascar hissing cockroaches is not a consequence of hysteresis around a fixed PCO2 threshold
Summary: Discontinuous gas exchange cycles in cockroaches do not arise from internal PCO2 oscillations around a fixed ventilatory threshold. DGCs continue when haemolymph PCO2 exceeds values recorded during continuous gas exchange.
Severe hypoxia exposure inhibits larval brain development but does not affect the capacity to mount a cortisol stress response in zebrafish
Summary: Severe acute hypoxia exposure in larval zebrafish significantly decreases forebrain neural proliferation but does not affect the long-term capacity to mount a cortisol stress response.
A heterothermic spectrum in hummingbirds
Editor's Choice: Three hummingbird species are capable of a temperature spectrum from normothermy to torpor, implying that some birds, at least, can precisely control their metabolic state.
Rapid blood acid–base regulation by European sea bass (Dicentrarchus labrax) in response to sudden exposure to high environmental CO2
Summary: European sea bass exposed to 1 kPa (10,000 µatm) CO2 regulate blood and red cell pH within 2 h and 40 min, respectively, protecting O2 transport capacity, via enhanced gill acid excretion.
Elastic energy storage across speeds during steady-state hopping of desert kangaroo rats (Dipodomys deserti)
Summary: The ankle extensor tendons of desert kangaroo rats store and return elastic energy in relation to hopping speed, recovering more energy at faster speeds.
Maternal food restriction during pregnancy affects offspring development and swimming performance in a placental live-bearing fish
Highlighted Article: Maternal food restriction during pregnancy results in smaller offspring, slower postnatal body fat gain and an inhibition of postnatal improvement of swimming skills during feeding, possibly leading to lower competitive abilities after birth.
Genetic variation in haemoglobin is associated with evolved changes in breathing in high-altitude deer mice
Highlighted Article: High-altitude variants in haemoglobin genes are associated with evolved changes in breathing that likely enhance O2 uptake in hypoxia in deer mice.
Behavioural responses of threespine stickleback with lateral line asymmetries to experimental mechanosensory stimuli
Summary: Stickleback with more mechanoreceptors have a stronger bias towards hovering with their right side adjacent to a surface when illuminated but a weaker bias in the dark.
CORRECTION
Call for Papers: The Integrative Biology of the Gut. Guest Editors Carol Bucking, Matt Regan and John Terblanche
We are pleased to welcome submissions for our upcoming Special Issue: The Integrative Biology of the Gut . We are calling for forward-looking papers that address the functional roles of the gut. We will consider papers that address gut function from the cellular level to its interactions with other organs and tissues, including its role in diverse ecophysiological processes, spanning both vertebrate and invertebrate species. The deadline for submission to this issue is 1 October 2024.
Extraordinary creatures: notothenioids and icefish
In our new Conversation focusing on extraordinary creatures, Christina Cheng and Kristin O'Brien tell us about the remarkable freeze tolerant nototheniods that live in the waters around Antarctica and how icefish are the only adult vertebrates that survive without haemoglobin.
Why are microclimates essential for predicting climate change responses and how to measure them?
In their Commentary, Duncan Mitchell and colleagues discuss problems with predicting terrestrial animals’ responses to a warming world based on air temperature, rather than the microclimate of their thermal environment. They provide a simple, low-cost approach to microclimate measurements to provide a more realistic assessment of terrestrial animal performance and predicted population responses in hot regions under warming conditions. This approach requires measuring the variables involved in the exchange of heat and water vapour between animals and their environment.
Keeping warm is harder for tree swallows when it’s damp
Damp air often feels chilly and now Cody Porter & co show that tree swallows use 8% more energy when the atmosphere is damp than when it is dry, so they have to work harder to keep warm in damp conditions.
Biologists @ 100 - join us in Liverpool in March 2025
We are excited to invite you to a unique scientific conference, celebrating the 100-year anniversary of The Company of Biologists, and bringing together our different communities. The conference will incorporate the Spring Meetings of the BSCB and the BSDB, the JEB Symposium Sensory Perception in a Changing World and a DMM programme on antimicrobial resistance. Find out more and register your interest to join us in March 2025 in Liverpool, UK.