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
The Integrative Biology of the Heart

We are pleased to welcome submissions to be considered for our upcoming special issue: The Integrative Biology of the Heart, guest edited by William Joyce and Holly Shiels. This issue will consider the biology of the heart at all levels of organisation, across animal groups and scientific fields.
JEB@100: an interview with Monitoring Editor John Terblanche

John Terblanche reveals how he narrowly avoided becoming a sports scientist and why he thinks phenotypic plasticity is the big question currently facing comparative physiologists. Find out more about the series on our Interviews page.
Vision 2024: Building Bridges in Visual Ecology

Early-career researchers can apply for funded places at our Vision 2024: Building Bridges in Visual Ecology. The event is organised by Eleanor Caves, Sonke Johnsen and Lorain Schweikert and being held at Buxted park 10-13 June 2023. Deadline 1 December 2023.
Reconciling the variability in the biological response of marine invertebrates to climate change

Drawing on work in reef-building corals, Zoe Dellaert and Hollie Putnam provide historical context to some of the long-standing challenges in global change biology that constrain our capacity for eco-evolutionary forecasting, as well as considering unresolved questions and future research approaches. Read the full Centenary Review Article here.
Sipping takes no effort for hovering hawkmoths

Hovering takes the most effort so how much energy does sipping require when hawkmoths hover? Next to nothing, apparently. Alexandre Palaoro & colleagues have discovered that the insects’ proboscises are incredibly wettable, drawing nectar along the length with no effort, giving them a free drink on the wing.