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1.
Accurate recognition requires that visual systems must be able to discriminate between target and distractor stimuli. Flowers are learned and recognised by bees using visual cues including colour and shape. We investigated whether bees were able to learn to discriminate between colours differently depending upon absolute or differential conditioning. For absolute conditioning bees were rewarded with sucrose solution for visits to target flowers. When distractor stimuli were subsequently presented, a high level of discrimination was observed if there was a perceptually large colour distance separating distractors and targets, but for a perceptually small colour distance the bees generalised and did not discriminate between stimuli. When provided with differential conditioning where both target and distractors were present, the bees learnt to discriminate stimuli separated by a perceptually small colour distance. This shows that for bees to learn fine colour discrimination tasks it is important to use differential conditioning. The findings are discussed within the context of the necessity for plants to produce distinctive flower colours. 相似文献
2.
Ivelize C. Tannure-Nascimento Fabio S. Nascimento José O. Dantas Ronaldo Zucchi 《Die Naturwissenschaften》2009,96(7):857-861
The capacity to distinguish colony members from strangers is a key component in social life. In social insects, this extends
to the brood and involves discrimination of queen eggs. Chemical substances communicate colony affiliation for both adults
and brood; thus, in theory, all colony members should be able to recognize fellow nestmates. In this study, we investigate
the ability of Dinoponera quadriceps workers to discriminate nestmate and non-nestmate eggs based on cuticular hydrocarbon composition. We analyzed whether cuticular
hydrocarbons present on the eggs provide cues of discrimination. The results show that egg recognition in D. quadriceps is related to both age and the functional role of workers. Brood care workers were able to distinguish nestmate from non-nestmate
eggs, while callow and forager workers were unable to do so.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
Caterpillars have many natural enemies and, therefore, have evolved a diversity of antipredator strategies. Most research
focuses on those strategies (crypsis, countershading, and warning coloration) targeting visually guided predators. In contrast,
defensive sounds, although documented for more than a century, have been poorly studied. We report on a novel form of sound
production—chirping—in caterpillars of the common European Great Peacock moth (Saturnia pyri). Chirps are broadband, with dominant peaks ranging between the sonic (3.7 kHz) and ultrasonic (55.1 kHz) and are generated
by a rapid succession of mandibular “tooth strikes.” Chirp trains are induced by simulated predator attacks and precede or
accompany the secretion of a defensive chemical from integumental bristles, supporting our hypothesis that these sounds function
in acoustic aposematism. We propose that these caterpillars generate multimodal warning signals (visual, chemical, and acoustic)
to target the dominant sensory modalities of different predators, including birds, bats, and invertebrates.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
The predatory pliosaurs were among the largest creatures ever to inhabit the oceans, some reaching gigantic proportions greater
than 15 m in length. Fossils of this subclade of plesiosaurs are known from sediments all over the world, ranging in age from
the Hettangian (approximately 198 Myr) to the Turonian (approximately 92 Myr). However, due to a lack of detailed studies
and because only incomplete specimens are usually reported, pliosaur evolution remains poorly understood. In this paper, we
describe the three dimensionally preserved skull of the giant Jurassic pliosaur Rhomaleosaurus cramptoni. The first phylogenetic analysis dedicated to in-group relationships of pliosaurs allows us to hypothesise a number of well-supported
lineages that correlate with marine biogeography and the palaeoecology of these reptiles. Rhomaleosaurids comprised a short-lived
and early diverging lineage within pliosaurs, whose open-water top-predator niche was filled by other pliosaur taxa by the
mid-late Jurassic.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
5.
Sex identification in female crayfish is bimodal 总被引:1,自引:0,他引:1
Sex identification has been studied in several species of crustacean decapods but only seldom was the role of multimodality investigated in a systematic fashion. Here, we analyse the effect of single/combined chemical and visual stimuli on the ability of the crayfish Procambarus clarkii to identify the sex of a conspecific during mating interactions. Our results show that crayfish respond to the offered stimuli depending on their sex. While males rely on olfaction alone for sex identification, females require the combination of olfaction and vision to do so. In the latter, chemical and visual stimuli act as non-redundant signal components that possibly enhance the female ability to discriminate potential mates in the crowded social context experienced during mating period. This is one of the few clear examples in invertebrates of non-redundancy in a bimodal communication system. 相似文献
6.
How is behaviour organised across sensory modalities? Specifically, we ask concerning the fruit fly Drosophila melanogaster how visual context affects olfactory learning and recall and whether information about visual context is getting integrated into olfactory memory. We find that changing visual context between training and test does not deteriorate olfactory memory scores, suggesting that these olfactory memories can drive behaviour despite a mismatch of visual context between training and test. Rather, both the establishment and the recall of olfactory memory are generally facilitated by light. In a follow-up experiment, we find no evidence for learning about combinations of odours and visual context as predictors for reinforcement even after explicit training in a so-called biconditional discrimination task. Thus, a ‘true’ interaction between visual and olfactory modalities is not evident; instead, light seems to influence olfactory learning and recall unspecifically, for example by altering motor activity, alertness or olfactory acuity. 相似文献
7.
Johannes Kroiss Erhard Strohm Cédric Vandenbem Jean-Pol Vigneron 《Die Naturwissenschaften》2009,96(8):983-986
Chrysidid wasps in the subfamily Chrysidinae are brood parasitoids or cleptoparasites of other insects and famous for their
cuticular iridescence. In this study, we examine the dorsal abdominal cuticle of the chrysidid wasp Hedychrum rutilans to identify the underlying color mechanism. Using scanning electron microscopy, reflectance spectral analysis, and theoretical
calculations, we demonstrate the presence of an epicuticular multilayer reflector consisting of six lamellae with a thickness
of 185 nm each. The lamellae exhibit a rough surface probably functioning as spacers between the individual layers. The reflector
has a measured reflectance maximum at λ = 630 nm, i.e., in the red part of the visible spectrum of light at normal incidence and the reflectance maximum shifts to
green as the angle of incidence increases. Complementary theoretical modeling corroborates the view that the epicuticular
multilayer generates the iridescent color of the chrysidid cuticle.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
Ryoko Matsumoto Shigeru Suzuki Khisigjav Tsogtbaatar Susan E. Evans 《Die Naturwissenschaften》2009,96(2):233-242
New material of the enigmatic diapsid Khurendukhosaurus is described from the Mongolian type locality, Khuren Dukh, providing additional data on the vertebral column, pelvis, and
hind limb. It confirms the choristoderan status of the genus and permits a more detailed phylogenetic analysis that supports
a relationship between Khurendukhosaurus and the long-necked Asian Hyphalosauridae. The existence of tall caudal neural spines implies that Khurendukhosaurus was a deep-tailed swimmer. This and the open sacral costocentral sutures suggest a primarily aquatic lifestyle.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Institutional abbreviations MNHN BL, Museum National d’Histoire Naturelle, Paris, France; MPC, Mongolian Paleontological Center; PIN, Paleontologicheski
Institut, Akademii Nauk, Moscow; HMNS, Hayashibara Museum of Natural Sciences, Okayama, Japan. 相似文献
9.
Pigeons released away from their loft usually fly around at the release site for a while before they finally leave. Visual
observations had suggested that the moment when the birds decide to head home is associated with a certain change in flying
style. To see whether this change is also reflected by GPS-recorded tracks, a group of pigeons equipped with flight recorders
was released at two sites about 10 km from their home loft. The initial part of their flight paths was analyzed in order to
find objective criteria indicating the point of decision. We selected the highest increase in steadiness as the best estimate
for the moment of decision. This criterion allows us to divide the pigeons’ paths in two distinct phases, an initial phase
and the homing phase, with the moment of decision, on an average, 2 min after release. The moment of decision marks a change
in behavior, with a significant increase in steadiness and flying speed and headings significantly closer to the home direction.
The behavior of the individual birds at the two sites was not correlated, suggesting no pronounced individual traits for the
length of the initial phase. The behavior during this phase seems to be controlled by flight preparation, exploration, and
non-navigational motivations rather than by navigational necessities alone.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
The hummingbird hawkmoth, Macroglossum stellatarum, learns colour fast and reliably. It has earlier been shown to spontaneously feed from odourless artificial flowers. Now, we have studied odour learning. The moths were trained to discriminate feeders of the same colour but marked with different odours. They did not learn to discriminate two natural flower odours when they were presented with the innately preferred colour blue, but they did learn this discrimination combined with yellow or green colours that are less attractive to the moth. The yellow colour could be trained to become as attractive as the innately preferred blue colour and the blue colour could be trained to become less attractive. This is the first proof of odour learning in a diurnal moth. The results show that M. stellatarum can use more than one modality in their foraging behaviour and that the system is plastic. By manipulating the preferences for the different colours, their influence on odour learning could be changed. 相似文献
11.
Living in a “stethoscope”: burrow-acoustics promote auditory specializations in subterranean rodents
Subterranean mammals rely to a great extent on audition for communication and to be alerted to danger. The only hitherto published
report on burrow acoustics revealed that in tunnels of blind mole-rats (Spalax ehrenbergi), airborne sounds of 440 Hz propagated best whereas lower and higher frequencies were effectively attenuated. Morpho-functional
analyses classify the ear of subterranean mammals as a low-sensitivity and low-frequency device. Concordantly, hearing is
characterized by low sensitivity and a restricted frequency range tuned to low frequencies (0.5–4 kHz). Some authors considered
the restricted hearing in subterranean mammals vestigial and degenerate due to under-stimulation. In contrast to this view
stand a rich (mostly low-frequency) vocal repertoire and progressive structural specializations of the middle and inner ear.
Thus, other authors considered these hearing characteristics adaptive. To test the hypothesis that acoustical environment
in burrows of different species of subterranean mammals is similar, we measured sound attenuation in burrows of Fukomys mole-rats (formerly known as Cryptomys, cf. Kock et al. 2006) of two differently sized species at different locations in Zambia. We show that in these burrows, low-frequency sounds (200–800 Hz)
are not only least attenuated but also their amplitude may be amplified like in a stethoscope (up to two times over 1 m).
We suggest that hearing sensitivity has decreased during evolution of subterranean mammals to avoid over-stimulation of the
ear in their natural environment.
We dedicate this work to Mathias Kawalika, who died in March 2006. 相似文献
12.
Flowers adapted for hummingbird pollination are typically red. This correlation is usually explained by the assertion that
nectar- or pollen-stealing bees are “blind” to red flowers. However, laboratory studies have shown that bees are capable of
locating artificial red flowers and often show no innate preference for blue over red. We hypothesised that these findings
might be artefacts of the simplified laboratory environment. Using bumblebees (Bombus impatiens) that had been trained to visit red and blue artificial flowers, we tested whether colour preference was influenced by complexity
of the background on which they were foraging. Many bees were indifferent to flower colour when tested using a uniform green
background like those commonly used in laboratory studies, but all bees showed strong colour preferences (usually for blue)
when flowers were presented against a photograph of real foliage. Overall, preference for blue flowers was significantly greater
on the more realistic, complex background. These results support the notion that the red of “hummingbird syndrome” flowers
can function to reduce bee visits despite the ability of bees to detect red and highlight the need to consider context when
drawing inferences about pollinator preferences from laboratory data.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
13.
Honeybees learn odor cues quickly and efficiently when visiting rewarding flowers. Memorization of these cues facilitates
the localization and recognition of food sources during foraging flights. Bees can also use information gained inside the
hive during social interactions with successful foragers. An important information cue that can be learned during these interactions
is food odor. However, little is known about how floral odors learned in the hive affect later decisions of foragers in the
field. We studied the effect of food scent on foraging preferences when this learning is acquired directly inside the hive.
By using in-hive feeders that were removed 24 h before the test, we showed that foragers use the odor information acquired
during a 3-day stimulation period with a scented solution during a food-choice situation outside the nest. This bias in food
preference is maintained even 24 h after the replacement of all the hive combs. Thus, without being previously collected outside
by foragers, food odors learned within the hive can be used during short-range foraging flights. Moreover, correct landings
at a dual-choice device after replacing the storing combs suggests that long-term memories formed within the colony can be
retrieved while bees search for food in the field. 相似文献
14.
The relative roles of the fish lateral line and inner ear for the perception of hydrodynamic stimuli are poorly investigated.
Here, we studied responsiveness to a 100 Hz vibrating sphere (dipole stimulus) of goldfish and oscars, two species that differ
in peripheral lateral line morphology, inner ear morphology, mechanical linkage between inner ear and swim bladder, and inner
ear sensitivity. We measured unconditioned dipole-evoked changes in breathing activity in still water and in the presence
of a 5-cm s−1 background flow. In still water, individuals from both species responded to sound pressure levels (SPLs) between 92 and 109 dB
SPL re 1 μPaRMS. Responsiveness was not affected by background flow or by temporary inactivation of the lateral line. The data suggest that
fish with different lateral line and inner ear morphologies have similar sensitivities to vibrating sphere stimuli and can
detect and respond to dipole sources equally well in still water and in moderate background flows. Moreover, behavioral responses
were not dependent on a functional lateral line, suggesting that in this type of experiment, the inner ear is the dominant
sense organ for the perception of hydrodynamic stimuli. 相似文献
15.
Kevin Lam Kelsie Thu Michelle Tsang Margo Moore Gerhard Gries 《Die Naturwissenschaften》2009,96(9):1127-1132
Female houseflies, Musca domestica (Diptera: Muscidae), lay their eggs in ephemeral resources such as animal manure. Hatching larvae compete for essential nutrients
with fungi that also colonize such resources. Both the well-known antagonistic relationship between bacteria and fungi and
the consistent presence of the bacterium Klebsiella oxytoca on housefly eggs led us to hypothesize (1) that K. oxytoca, and possibly other bacteria on housefly eggs, help curtail the growth of fungal resource competitors and (2) that such fungi
indeed adversely affect the development of housefly larvae. Bacteria washed from housefly eggs significantly reduced the growth
of fungi in chicken manure. Nineteen bacterial strains and ten fungal strains were isolated from housefly eggs or chicken
manure, respectively. Co-culturing each of all the possible bacterium–fungus pairs revealed that the bacteria as a group,
but no single bacterium, significantly suppressed the growth of all fungal strains tested. The bacteria's adverse effect on
fungi is due to resource nutrient depletion and/or the release of antifungal chemicals. Well-established fungi in resources
significantly reduced the number of larval offspring that completed development to adult flies.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
An absence of aggression between non-nestmates in the bull ant <Emphasis Type="Italic">Myrmecia nigriceps</Emphasis> 总被引:2,自引:0,他引:2
van Wilgenburg E Dang S Forti AL Koumoundouros TJ Ly A Elgar MA 《Die Naturwissenschaften》2007,94(9):787-790
The ability of social insects to discriminate against non-nestmates is vital for maintaining colony integrity, and in most
social insect species, individuals act aggressively towards non-nestmates that intrude into their nest. Our experimental field
data revealed that intra-colony aggression in the primitive bulldog ant Myrmecia nigriceps is negligible; our series of bioassays revealed no significant difference in the occurrence of aggression in trials involving
workers from the same, a close (less than 300 m) or a far (more than 1.5 km) nest. Further, non-nestmate intruders were able
to enter the nest in 60% of our trials; a similar level was observed in trials involving nestmates. These results suggest
that workers of M. nigriceps are either unable to recognize alien conspecifics or that the costs of ignoring workers from foreign colonies are sufficiently
low to favor low levels of inter-colony aggression in this species. 相似文献
17.
Müller J 《Die Naturwissenschaften》2003,90(10):473-476
The temporal arches of diapsid reptiles have received attention for several decades. In particular, it has been observed that the lower temporal bar at the ventral margin of the cheek is frequently reduced due to the absence of a contact between jugal and quadratojugal. The loss of the arcade was formerly considered to be of high systematic value, but is now often interpreted as being autapomorphic for the respective taxon, and the presence of both arcades is generally regarded as a plesiomorphic feature. Here I show, based on a cladistic analysis as well as on further anatomical evidence, that the lower temporal arcade was lost only once in diapsid evolution, and that the presence of the arch in "higher" diapsids is secondary, which is indicated by the different ratio between jugal and quadratojugal as well as by ontogeny. This result also sheds new light on the understanding of the cheek configuration of enigmatic taxa such as ichthyosaurs and turtles.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material. 相似文献
18.
The ability of many insects to learn has been documented. However, a limited number of studies examining associative learning in medically important arthropods has been published. Investigations into the associative learning capabilities of Culex
quinquefasciatus Say were conducted by adapting methods commonly used in experiments involving Hymenoptera. Male and female mosquitoes were able to learn a conditioned stimulus that consisted of an odor not normally encountered in nature (synthetic strawberry or vanilla extracts) in association with an unconditioned stimulus consisting of either a sugar (males and females) or blood (females) meal. Such information could lead to a better understanding of the ability of mosquitoes to locate and select host and food resources in nature. 相似文献
19.
Laura Domingo Stephen T. Grimes M. Soledad Domingo M. Teresa Alberdi 《Die Naturwissenschaften》2009,96(4):503-511
Expansion of C4 grasses during Late Miocene and Early Pliocene constitutes one of the most remarkable biotic events of the Cenozoic era.
The Teruel–Alfambra region (northeastern Spain) contains one of the most complete Miocene–Pliocene sequences of mammalian
fossil sites in the world. In this study, stable isotope (δ
13C and δ
18O) analyses have been performed on the tooth enamel from the equid Hipparion from 19 localities spanning a time interval from approximately 10.9 to 2.7 Ma. This time range starts with the first appearance
of this genus in Spain and ends at its extinction. An increase in δ
13C at about 4.2 Ma has been observed, indicative of a shift toward a more open habitat. This shift may be related to a large
scale vegetation change which occurred across the Miocene–Pliocene boundary when C4 grasses expanded. This expansion might in turn be linked to global tectonic events such as the uplift of the Himalaya and/or
the closure of the Panama Isthmus. However, other more regional factors may have ultimately enhanced the trend toward more
open habitats in the Western Mediterranean Basin. The Messinian Salinity Crisis was a major environmental event that may have
been responsible for the isotopic changes seen in the equid Hipparion from the Iberian Peninsula along with an increase in the aridity detected ~4.6 Ma ago in the Sahara. Even though the exact
factor triggering the isotopic change observed in the Hipparion enamel remains mostly unknown, this study demonstrates that the global environmental changes detected across the Miocene–Pliocene
boundary are also recorded in the realm of the Iberian Peninsula.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
20.
Sharks are apex predators, and their evolutionary success is in part due to an impressive array of sensory systems, including
vision. The eyes of sharks are well developed and function over a wide range of light levels. However, whilst close relatives
of the sharks—the rays and chimaeras—are known to have the potential for colour vision, an evolutionary trait thought to provide
distinct survival advantages, evidence for colour vision in sharks remains equivocal. Using single-receptor microspectrophotometry,
we measured the absorbance spectra of visual pigments located in the retinal photoreceptors of 17 species of shark. We show
that, while the spectral tuning of the rod (wavelength of maximum absorbance, λmax 484–518 nm) and cone (λmax 532–561 nm) visual pigments varies between species, each shark has only a single long-wavelength-sensitive cone type. This
suggests that sharks may be cone monochromats and, therefore, potentially colour blind. Whilst cone monochromacy on land is
rare, it may be a common strategy in the marine environment: many aquatic mammals (whales, dolphins and seals) also possess
only a single, green-sensitive cone type. It appears that both sharks and marine mammals may have arrived at the same visual
design by convergent evolution. The spectral tuning of the rod and cone pigments of sharks is also discussed in relation to
their visual ecology. 相似文献