Αρχειοθήκη ιστολογίου

Τετάρτη 26 Ιουνίου 2019

The paradox of hearing at the lek: auditory sensitivity increases after breeding in female gray treefrogs ( Hyla chrysoscelis )
Abstract Both behavioral receptivity and neural sensitivity to acoustic mate attraction signals vary across the reproductive cycle, particularly in seasonally breeding animals. Across a variety of taxa receptivity to signals increases, as does peripheral auditory sensitivity, as females transition from a non-breeding to breeding condition. We recently documented decreases in receptivity to acoustic mate attraction signals and circulating hormone levels, but an increase in peripheral...
Latest Results for Journal of Comparative Physiology A
6m
A magnetic compass guides the direction of foraging in a bat
Abstract Previously, two studies have provided evidence that bats can use magnetic field cues for homing or roosting. For insectivorous bats, it is well established that foraging represents one of the most fundamental behaviors in animals relies on their ability to echolocate. Whether echolocating bats can also use magnetic cues during foraging remains unknown, however. Here, we tested the orientation behavior of Chinese noctules (Nyctalus plancyi) during foraging in a plus-shaped,...
Latest Results for Journal of Comparative Physiology A
6m

Appetite is correlated with octopamine and hemolymph sugar levels in forager honeybees
Abstract Insects have rapidly changing energy demands, so they primarily rely on hemolymph and other carbohydrates to carry out life activities. However, how gustatory responsiveness and hemolymph sugar levels coordinate with one another to maintain energetic homeostasis in insects remains largely unknown for the highly social honeybee that goes through large physiological and behavioral changes. The potential role of biogenic amines and neuropeptides in the connection between...
Latest Results for Journal of Comparative Physiology A
6m
Calbindin-D 28k expression in spinal electromotoneurons of the weakly electric fish Apteronotus leptorhynchus during adult development and regeneration
Abstract Additive neurogenesis, the net increase in neuronal numbers by addition of new nerve cells to existing tissue, forms the basis for indeterminate spinal cord growth in brown ghost knifefish (Apteronotus leptorhynchus). Among the cells generated through the activity of adult neural stem cells are electromotoneurons, whose axons constitute the electric organ of this weakly electric fish. Electromotoneuron development is organized along a caudo-rostral gradient, with the youngest...
Latest Results for Journal of Comparative Physiology A
7m
Colour preferences of Tetragonula carbonaria Sm. stingless bees for colour morphs of the Australian native orchid Caladenia carnea
Abstract Innate colour preferences promote the capacity of pollinators to find flowers, although currently there is a paucity of data on how preferences apply to real flowers. The Australian sugarbag bee (Tetragonula carbonaria Sm.) has innate preferences for colours, including UV-absorbing white. Sugarbag bees are pollinators of the terrestrial orchid Caladenia carnea R.Br., which has both white and pink morphs. In laboratory conditions, we tested flower-naïve bees with the...
Latest Results for Journal of Comparative Physiology A
7m
Image statistics of the environment surrounding freely behaving hoverflies
Abstract Natural scenes are not as random as they might appear, but are constrained in both space and time. The 2-dimensional spatial constraints can be described by quantifying the image statistics of photographs. Human observers perceive images with naturalistic image statistics as more pleasant to view, and both fly and vertebrate peripheral and higher order visual neurons are tuned to naturalistic image statistics. However, for a given animal, what is natural differs depending...
Latest Results for Journal of Comparative Physiology A
7m
Speciation, pattern recognition and the maximization of pollination: general questions and answers given by the reproductive biology of the orchid genus Ophrys
Abstract Pollination syndromes evolved under the reciprocal selection of pollinators and plants (coevolution). Here, the two main methods are reviewed which are applied to prove such selection. (i) The indirect method is a cross-lineage approach using phylogenetical trees to understand the phylogeny. Thus, features of single origin can be distinguished from those with multiple origins. Nearly all pollination modes originate in multiple evolutionary ways. (ii) The most frequent...
Latest Results for Journal of Comparative Physiology A
7m
Honeybees foraging for numbers
Abstract The capacity to process numbers can be found in many vertebrate species, which share similar behavioral and neural mechanisms for number estimation. Honeybees possess a miniature brain but exhibit remarkable cognitive abilities, including the capacity to perform numerosity judgments in a foraging context. Honeybee foragers can count up to four landmarks en route to the goal and use this information to decide where to land. They also learn to match visual images based...
Latest Results for Journal of Comparative Physiology A
7m
Cross-modal transfer in visual and nonvisual cues in bumblebees
Abstract Bumblebees Bombus terrestris are good at learning to distinguish between patterned flowers. They can differentiate between flowers that differ only in their patterning of scent, surface texture, temperature, or electrostatic charge, in addition to visual patterns. As recently shown, bumblebees trained to discriminate between nonvisual scent patterns can transfer this learning to visually patterned flowers that show similar spatial patterning to the learnt scent patterns....
Latest Results for Journal of Comparative Physiology A
7m
Vividly coloured poppy flowers due to dense pigmentation and strong scattering in thin petals
Abstract The flowers of poppies (Papaveraceae) exhibit bright colours, despite their thin and floppy petals. We investigated the optical properties of flowers of Papaver rhoeas, P. dubium, Meconopsis cambrica and Argemone polyanthemos using a combined approach of anatomy, spectrophotometry and optical modelling. The petals of Papaver flowers are composed of only three cell layers, an upper and lower epidermal layer, which are densely filled with pigment, and an unpigmented mesophyll...
Latest Results for Journal of Comparative Physiology A
7m
Bumblebees are able to perceive amino acids via chemotactile antennal stimulation
Abstract Like all animals, bees need to consume essential amino acids to maintain their body’s protein synthesis. Perception and discrimination of amino acids are, however, still poorly understood in bees (and insects in general). We used chemotactile conditioning of the proboscis extension response (PER) to examine (1) whether Bombus terrestris workers are able to perceive amino acids by means of their antennae and (if so) which ones, (2) whether they are able to differentiate...
Latest Results for Journal of Comparative Physiology A
7m
Fuelling on the wing: sensory ecology of hawkmoth foraging
Abstract Hawkmoths (Lepidoptera, Sphingidae) comprise around 1500 species, most of which forage on nectar from flowers in their adult stage, usually while hovering in front of the flower. The majority of species have a nocturnal lifestyle and are important nocturnal pollinators, but some species have turned to a diurnal lifestyle. Hawkmoths use visual and olfactory cues including CO2 and humidity to detect and recognise rewarding flowers; they find the nectary in the flowers...
Latest Results for Journal of Comparative Physiology A
7m
One of the most fascinating stories in biology
Latest Results for Journal of Comparative Physiology A
7m
Foraging strategies and physiological adaptations in large carpenter bees
Abstract Large carpenter bees are charismatic and ubiquitous flower visitors in the tropics and sub-tropics. Unlike honeybees and bumblebees that have been popular subjects of extensive studies on their neuroethology, behaviour and ecology, carpenter bees have received little attention. This review integrates what is known about their foraging behaviour as well as sensory, physiological and cognitive adaptations and is motivated by their versatility as flower visitors and pollinators....
Latest Results for Journal of Comparative Physiology A
7m
Stingless bees and their adaptations to extreme environments
Abstract Nearly half of all terrestrial tropical ecosystems around the globe comprise dry forests, characterised through elevated temperatures all year round, and short rainy seasons at irregular intervals. The consequent water deficit over several consecutive months limits the availability of floral resources to often very brief and unpredictable periods, which poses a challenge to the maintenance of perennial colonies in highly eusocial bees. Thus, only few highly eusocial...
Latest Results for Journal of Comparative Physiology A
7m
Stored perfume dynamics and consequences for signal development in male orchid bees
Abstract Male orchid bees (Euglossini) collect volatiles from their environment to concoct species-specific “perfumes”, which are later emitted at mating sites. Intensity, complexity or composition of perfumes may encode age (survival) of a male, but how the individual perfume develops over time needs to be clarified. We investigated chemical changes during storage in leg pockets. We injected a mixture of eight perfume compounds into pockets of Euglossa imperialis and only the...
Latest Results for Journal of Comparative Physiology A
7m
Flower scent of Ceropegia stenantha : electrophysiological activity and synthesis of novel components
Abstract In specialized pollination systems, floral scents are crucial for flower–pollinator communication, but key volatiles that attract pollinators are unknown for most systems. Deceptive Ceropegia trap flowers are famous for their elaborate mechanisms to trap flies. Recent studies revealed species-specific floral chemistry suggesting highly specialized mimicry strategies. However, volatiles involved in fly attraction were until now identified in C. dolichophylla and C. sandersonii,...
Latest Results for Journal of Comparative Physiology A
7m
A matter of taste: the adverse effect of pollen compounds on the pre-ingestive gustatory experience of sugar solutions for honeybees
Abstract In addition to sugars, nectar contains multiple nutrient compounds in varying concentrations, yet little is known of their effect on the reward properties of nectar and the resulting implications for insect behaviour. We examined the pre-ingestive responses of honeybees to sucrose solutions containing a mix of pollen compounds, the amino acids proline or phenylalanine, or known distasteful substances, quinine and salt. We predicted that in taste and learning assays,...
Latest Results for Journal of Comparative Physiology A
7m
Bats are unusually insensitive to brief low-frequency tones
Abstract Bats use brief calls for echolocation, suggesting that they might be more sensitive to brief sounds than non-echolocating mammals. To investigate this possibility, absolute thresholds for brief tones were determined for four species of bats: The Common vampire bat (Desmodus rotundus) and the Greater spear-nosed bat (Phyllostomus hastatus), both of which use frequency-modulated calls, the Egyptian fruit bat (Rousettus aegyptiacus), an echolocator that uses tongue-clicks...
Latest Results for Journal of Comparative Physiology A
7m
The plus maze and scototaxis test are not valid behavioral assays for anxiety assessment in the South African clawed frog
Abstract There are no behavioral models for testing anxiety in amphibians, a group of animals widely used for developmental, ecotoxicological, and genetic research. We aimed to validate two common rodent paradigms, the plus maze and the scototaxis test, for use in the aquatic African clawed frog (Xenopus laevis). We predicted: (a) that frogs would prefer the dark, vs. light, portions of the testing arenas (face validity), (b) that this behavior could be altered with acute administration...
Latest Results for Journal of Comparative Physiology A
7m

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