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1.
Polarization-Sensitive Interneurons in the Optic Lobe of the Desert Ant Cataglyphis bicolor 总被引:1,自引:0,他引:1
Labhart T 《Die Naturwissenschaften》2000,87(3):133-136
Desert ants, Cataglyphis bicolor (Hymenoptera), navigate by using compass information provided by skylight polarization. In this study, electrophysiological
recordings were made from polarization-sensitive interneurons (POL-neurons) in the optic lobe of Cataglyphis. The POL-neurons exhibit a characteristic polarization opponency. They receive monochromatic input from the UV receptors
of the specialized dorsal rim area of the compound eye. Both polarization opponency and monochromacy are features also found
in the POL-neurons of crickets (Orthoptera).
Received: 29 September 1999 / Accepted in revised form: 13 December 1999 相似文献
2.
The queenless ant Pristomyrmex punctatus (Hymenoptera: Myrmicinae) has a unique society that differs from those of other typical ants. This species does not have
a queen, and the workers lay eggs and produce their clones parthenogenetically. However, a colony of these ants does not always
comprise members derived from a single clonal line. In this study, we examined whether P. punctatus changes its “assembling behavior” based on colony genetic structure. We prepared two subcolonies—a larger one comprising
200 individuals and a smaller one comprising 100 individuals; these subcolonies were established from a single stock colony.
We investigated whether these subcolonies assemble into a single nest. The genetically monomorphic subcolonies (single clonal
line) always fused into a single nest; however, the genetically polymorphic subcolonies (multiple clonal lines) did not tend
to form a single colony. The present study is the first to demonstrate that the colony genetic structure significantly affects
social viscosity in social insects. 相似文献
3.
In search of the sky compass in the insect brain 总被引:2,自引:0,他引:2
Homberg U 《Die Naturwissenschaften》2004,91(5):199-208
Like many vertebrate species, insects rely on a sun compass for spatial orientation and long- range navigation. In addition to the sun, however, insects can also use the polarization pattern of the sky as a reference for estimating navigational directions. Recent analysis of polarization vision pathways in the brain of orthopteroid insects sheds some light onto brain areas that might act as internal navigation centers. Here I review the significance, peripheral mechanisms, and central processing stages for polarization vision in insects with special reference to the locust Schistocerca gregaria. As in other insect species, polarization vision in locusts relies on specialized photoreceptor cells in a small dorsal rim area of the compound eye. Stages in the brain involved in polarized light signaling include specific areas in the lamina, medulla and lobula of the optic lobe and, in the midbrain, the anterior optic tubercle, the lateral accessory lobe, and the central complex. Integration of polarized-light signals with information on solar position appears to start in the optic lobe. In the central complex, polarization-opponent interneurons form a network of interconnected neurons. The organization of the central complex, its connections to thoracic motor centers, and its involvement in the spatial control of locomotion strongly suggest that it serves as a spatial organizer within the insect brain, including the functions of compass orientation and path integration. Time compensation in compass orientation is possibly achieved through a neural pathway from the internal circadian clock in the accessory medulla to the protocerebral bridge of the central complex. 相似文献
4.
Orientation and navigation during adult transport between nests in the ant Cataglypis iberica 总被引:1,自引:0,他引:1
Cataglyphis iberica is a polydomous ant species in which adult transports between nests are frequently observed. When pairs of workers were captured
and released at the same location, the transporters (Ts) fled directly towards their destination nest and reached it in most
of the cases. The transportees (Te), on the other hand, fled in the opposite direction and only a third of them eventually
reached their nest of departure. Additional experiments suggest that this result may be explained by the fact that the Ts
ants have a memory of the compass direction of the nest they are heading to and that they adjust their course by using a sequence
of memorised landmarks. As regards to the Te, the reversal of their direction of transport seems to be based essentially on
celestial cues.
Received: 20 October 1999 / Accepted in revised form: 10 May 2000 相似文献
5.
Homing pigeons are well known as good homers, and the knowledge of principal parameters determining their homing behaviour
and the neurological basis for this have been elucidated in the last decades. Several orientation mechanisms and parameters—sun
compass, earth’s magnetic field, olfactory cues, visual cues—are known to be involved in homing behaviour, whereas there are
still controversial discussions about their detailed function and their importance. This paper attempts to review and summarise
the present knowledge about pigeon homing by describing the known orientation mechanisms and factors, including their pros
and cons. Additionally, behavioural features like motivation, experience, and track preferences are discussed. All behaviour
has its origin in the brain and the neuronal basis of homing and the neuroanatomical particularities of homing pigeons are
a main topic of this review. Homing pigeons have larger brains in comparison to other non-homing pigeon breeds and particularly
show increased size of the hippocampus. This underlines our hypothesis that there is a relationship between hippocampus size
and spatial ability. The role of the hippocampus in homing and its plasticity in response to navigational experience are discussed
in support of this hypothesis. 相似文献
6.
Here, we provide evidence for a wavelength-dependent effect of light on magnetic compass orientation in Pelophylax perezi (order Anura), similar to that observed in Rana catesbeiana (order Anura) and Notophthalmus viridescens (order Urodela), and confirm for the first time in an anuran amphibian that a 90° shift in the direction of magnetic compass
orientation under long-wavelength light (≥500 nm) is due to a direct effect of light on the underlying magnetoreception mechanism.
Although magnetic compass orientation in other animals (e.g., birds and some insects) has been shown to be influenced by the
wavelength and/or intensity of light, these two amphibian orders are the only taxa for which there is direct evidence that
the magnetic compass is light-dependent. The remarkable similarities in the light-dependent magnetic compasses of anurans
and urodeles, which have evolved as separate clades for at least 250 million years, suggest that the light-dependent magnetoreception
mechanism is likely to have evolved in the common ancestor of the Lissamphibia (Early Permian, ~294 million years) and, possibly,
much earlier. Also, we discuss a number of similarities between the functional properties of the light-dependent magnetic
compass in amphibians and blue light-dependent responses to magnetic stimuli in Drosophila melanogaster, which suggest that the wavelength-dependent 90° shift in amphibians may be due to light activation of different redox forms
of a cryptochrome photopigment. Finally, we relate these findings to earlier studies showing that the pineal organ of newts
is the site of the light-dependent magnetic compass and recent neurophysiological evidence showing magnetic field sensitivity
in the frog frontal organ (an outgrowth of the pineal). 相似文献
7.
Martin Heil Brigitte Fiala K. Eduard Linsenmair Thomas Boller 《Die Naturwissenschaften》1999,86(3):146-149
Many plant species have evolved mutualistic associations with ants, protecting their host against detrimental influences
such as herbivorous insects. Letourneau (1998) reported in the case of Piper that ants defend their plants principally against stem-boring insects and also reduce fungal infections on inflorescences.
Macaranga plants that were experimentally deprived of their symbiotic Crematogaster ants suffered heavily from shoot borers and pathogenic fungi (Heil 1998). Here we report that ants seem to reduce fungal infections
actively in the obligate myrmecophyte Macaranga
triloba (Euphorbiaceae), while ant-free plants can be easily infected. We also found extremely low chitinase activity in Macaranga plants. The plants' own biochemical defense seems to be reduced, and low chitinase activity perhaps may represent a predisposition
for the evolution of myrmecophytism. These plants are therefore highly dependent on their ants, which obviously function not
only as an antiherbivore defense but also as an effective agent against fungal pathogens.
Received: 5 August 1998 / Accepted in revised form: 18 November 1998 相似文献
8.
In ants, winged queens that are specialized for independent colony foundation can be replaced by wingless reproductives better
adapted for colony fission. We studied this shift in reproductive strategy by comparing two Mystrium species from Madagascar using morphometry, allometry and dissections. Mystrium rogeri has a single dealate queen in each colony with a larger thorax than workers and similar mandibles that allow these queens
to hunt during non-claustral foundation. In contrast, Mystrium ‘red’ lacks winged queens and half of the female adults belong to a wingless ‘intermorph’ caste smaller and allometrically distinct
from the workers. Intermorphs have functional ovaries and spermatheca while those of workers are degenerate. Intermorphs care
for brood and a few mate and reproduce making them an all-purpose caste that takes charge of both work and reproduction. However,
their mandibles are reduced and inappropriate for hunting centipedes, unlike the workers’ mandibles. This together with their
small thorax disallow them to perform independent colony foundation, and colonies reproduce by fission. M. rogeri workers have mandibles polymorphic in size and shape, which allow for all tasks from brood care to hunting. In M. ‘red’, colonial investment in reproduction has shifted from producing expensive winged queens to more numerous helpers. M. ‘red’ intermorphs are the first case of reproductives smaller than workers in ants and illustrate their potential to diversify
their caste system for better colonial economy. 相似文献
9.
Kost C Lakatos T Böttcher I Arendholz WR Redenbach M Wirth R 《Die Naturwissenschaften》2007,94(10):821-828
Fungus-growing ants and their fungal cultivar form a highly evolved mutualism that is negatively affected by the specialized
parasitic fungus Escovopsis. Filamentous Pseudonocardia bacteria occurring on the cuticle of attine ants have been proposed to form a mutualistic interaction with these ants in
which they are vertically transmitted (i.e. from parent to offspring colonies). Given a strictly vertical transmission of
Pseudonocardia, the evolutionary theory predicts a reduced genetic variability of symbionts among ant lineages. The aim of this study was
to verify whether actinomycetes, which occur on Acromyrmex octospinosus leaf-cutting ants, meet this expectation by comparing their genotypic variability with restriction fragment length polymorphisms.
Multiple actinomycete strains could be isolated from both individual ant workers and colonies (one to seven strains per colony).
The colony specificity of actinomycete communities was high: Only 15% of all strains were isolated from more than one colony,
and just 5% were present in both populations investigated. Partial sequencing of 16S ribosomal deoxyribonucleic acid of two
of the isolated strains assigned both of them to the genus Streptomyces. Actinomycetes could also be isolated from workers of the two non-attine ant species Myrmica rugulosa and Lasius flavus. Sixty-two percent of the strains derived from attine ants and 80% of the strains isolated from non-attine ants inhibited
the growth of Escovopsis. Our data suggest that the association between attine ants and their actinomycete symbionts is less specific then previously
thought. Soil-dwelling actinomycetes may have been dynamically recruited from the environment (horizontal transmission), probably
reflecting an adaptation to a diverse community of microbial pathogens. 相似文献
10.
Previous experiments on wild rock doves ( Columba l. livia Gmelin) released within their familiar area revealed an evident effect of fast-shifting, although shifted doves, but not controls, tended to orient homeward. Such an outcome suggested a possible influence of the release time per se on the directional choices of the tested doves. In the present study, this hypothesis was investigated by comparing the orientation of slow-shifted birds to that of two control groups released at different times of the day. As would be expected if doves make use of a time-compensated sun compass, the bearings of shifted birds were deflected clockwise with respect to controls. The time of release itself seemed to influence only the scatter of the vanishing bearings of controls. These findings testify to the substantial similarity of clock-shift effects on the initial orientation of rock doves to those on homing pigeons released from familiar sites. 相似文献
11.
In holometabolous insects, pupation site selection behaviour has large consequences for survival. Here, we investigated the
combined effects of temperature and parasitism by the parasitoid Asobara tabida on larval pupation behaviour in two of its main Drosophila sp. hosts differing in their climate origin. We found that larvae of Drosophila melanogaster—a species with a (sub)tropical origin—placed at 25°C pupated higher in rearing jars than those placed at 15°C. The opposite
pattern was observed for Drosophila subobscura larvae—a species from temperate regions—which pupated lower, i.e. on or near the substrate at 25°C, than those placed at
15°C. When placed at 25°C, parasitized larvae of both species pupated closer to the substrate than unparasitized ones. Moreover,
the Drosophila larvae that had been exposed and probably stung by A. tabida, but were not parasitized, pupated lower than the control unparasitized larvae. These results provide new insights of host
behaviour manipulation by A. tabida larvae. 相似文献
12.
Social harmony often relies on ritualised dominance interactions between society members, particularly in queenless ant societies,
where colony members do not have developmentally predetermined castes but have to fight for their status in the reproductive
and work hierarchy. In this behavioural plasticity, their social organisation resembles more that of vertebrates than that
of the “classic” social insects. The present study investigates the neurochemistry of the queenless ant species, Streblognathus peetersi, to better understand the neural basis of the high behavioural plasticity observed in queenless ants. We report measurements
of brain biogenic amines [octopamine, dopamine, serotonin] of S. peetersi ants; they reveal a new set of biogenic amine influences on social organisation with no common features with other “primitively
organised societies” (bumble bees) and some common features with “highly eusocial” species (honey bees). This similarity to
honey bees may either confirm the heritage of queenless species from their probably highly eusocial ancestors or highlight
independent patterns of biogenic amine influences on the social organisation of these highly derived species. 相似文献
13.
Animal lifespans range from a few days to many decades, and this life history diversity is especially pronounced in ants.
Queens can live for decades. Males, in contrast, are often assumed to act as ephemeral sperm delivery vessels that die after
a brief mating flight—a view developed from studies of lekking species in temperate habitats. In a tropical ant assemblage,
we found that males can live days to months outside the nest, a trait hypothesized to be associated with female calling, another
common mating system. We combined feeding experiments with respirometry to show that lifespan can be enhanced over 3 months
by feeding outside the nest. In one focal female calling species, Ectatomma ruidum, feeding enhanced male lifespan, but not sperm content. Extended lifespans outside the nest suggest stronger than expected
selection on premating traits of male ants, although the ways these traits shape male mating success remain poorly understood. 相似文献
14.
We determined chitinase activity in leaves of four myrmecophytic and four non-myrmecophytic leguminous species at the plants'
natural growing sites in Mexico. Myrmecophytic plants (or 'ant plants') have obligate mutualisms with ants protecting them
against herbivores and pathogenic fungi. Plant chitinases can be considered a reliable measure of plant resistance to pathogenic
fungi. The myrmecophytic Acacia species, which were colonised by mutualistic ants, exhibited at least six-fold lower levels of chitinase activity compared
with the non-myrmecophytic Acacia farnesiana and three other non-myrmecophytes. Though belonging to different phylogenetic groups, the myrmecophytic Acacia species formed one distinct group in the data set, which was clearly separated from the non-myrmecophytic species. These
findings allowed for comparison between two recent hypotheses that attempt to explain low chitinase activity in ant plants.
Most probably, chitinases are reduced in myrmecophytic plant species because these are effectively defended indirectly due
to their symbiosis with mutualistic ants.
Received: 16 August 2000 / Accepted in revised form: 28 October 2000 相似文献
15.
Although associations between myrmecophytes and their plant ants are recognized as a particularly effective form of protective
mutualism, their functioning remains incompletely understood. This field study examined the ant-plant Hirtella physophora and its obligate ant associate Allomerus decemarticulatus. We formulated two hypotheses on the highly specific nature of this association: (1) Ant presence should be correlated with
a marked reduction in the amount of herbivory on the plant foliage; (2) ant activity should be consistent with the "optimal
defense" theory predicting that the most vulnerable and valuable parts of the plant are the best defended. We validated the
first hypothesis by demonstrating that for ant-excluded plants, expanding leaves, but also newly matured ones in the long
term, suffered significantly more herbivore damage than ant-inhabited plants. We showed that A. decemarticulatus workers represent both constitutive and inducible defenses for their host, by patrolling its foliage and rapidly recruiting
nestmates to foliar wounds. On examining how these activities change according to the leaves’ developmental stage, we found
that the number of patrolling ants dramatically decreased as the leaves matured, while leaf wounds induced ant recruitment
regardless of the leaf’s age. The resulting level of these indirect defenses was roughly proportional to leaf vulnerability
and value during its development, thus validating our second hypothesis predicting optimal protection. This led us to discuss
the factors influencing ant activity on the plant’s surface. Our study emphasizes the importance of studying both the constitutive
and inducible components of indirect defense when evaluating its efficacy and optimality. 相似文献
16.
Joseph C. Spagna Adam Schelkopf Tiana Carrillo Andrew V. Suarez 《Die Naturwissenschaften》2009,96(2):243-250
Evolutionary co-option of existing structures for new functions is a powerful yet understudied mechanism for generating novelty.
Trap-jaw ants of the predatory genus Odontomachus are capable of some of the fastest self-propelled appendage movements ever recorded; their devastating strikes are not only
used to disable and capture prey, but produce enough force to launch the ants into the air. We tested four Odontomachus species in a variety of behavioral contexts to examine if their mandibles have been co-opted for an escape mechanism through
ballistic propulsion. We found that nest proximity makes no difference in interactions with prey, but that prey size has a
strong influence on the suite of behaviors employed by the ants. In trials involving a potential threat (another trap-jaw
ant species), vertical jumps were significantly more common in ants acting as intruders than in residents (i.e. a dangerous
context), while horizontal jumps occurred at the same rate in both contexts. Additionally, horizontal jump trajectories were
heavily influenced by the angle at which the substrate was struck and appear to be under little control by the ant. We conclude
that while horizontal jumps may be accidental side-effects of strikes against hard surfaces, vertical escape jumps are likely
intentional defensive behaviors that have been co-opted from the original prey-gathering and food-processing functions of
Odontomachus jaws. 相似文献
17.
18.
The behavioral response of the obligate bamboo-nesting ant Cataulacus muticus to nest flooding was studied in a perhumid tropical rainforest in Malaysia and in the laboratory. The hollow internodes of
giant bamboo, in which C. muticus exclusively nests, are prone to flooding by heavy rains. The ants showed a two-graded response to flooding. During heavy
rain workers block the nest entrances with their heads to reduce water influx. However, rainwater may still intrude into the
nest chamber. The ants respond by drinking the water, leaving the nest and excreting water droplets on the outer stem surface.
This cooperative 'peeing' behavior is a new survival mechanism adaptive to the ants' nesting ecology. Laboratory experiments
conducted with two other Cataulacus species, C. catuvolcus colonizing small dead twigs and C. horridus inhabiting rotten wood, did not reveal any form of water-bailing behavior.
Received: 3 August 2000 / Accepted in revised form: 6 November 2000 相似文献
19.
Wind has previously been shown to influence the location and orientation of spider web sites and also the geometry and material
composition of constructed orb webs. We now show that wind also influences components of prey-catching behaviour within the
web. A small wind tunnel was used to generate different wind speeds. Araneus diadematus ran more slowly towards entangled Drosophila melanogaster in windy conditions, which took less time to escape the web. This indicates a lower capture probability and a diminished
overall predation efficiency for spiders at higher wind speeds. We conclude that spiders’ behaviour of taking down their webs
as wind speed increases may therefore not be a response only to possible web damage. 相似文献
20.
Wasps robbing food from ants: a frequent behavior? 总被引:1,自引:0,他引:1
Food robbing, or cleptobiosis, has been well documented throughout the animal kingdom. For insects, intrafamilial food robbing
is known among ants, but social wasps (Vespidae; Polistinae) taking food from ants has, to the best of our knowledge, never
been reported. In this paper, we present two cases involving social wasps robbing food from ants associated with myrmecophytes.
(1) Polybioides tabida F. (Ropalidiini) rob pieces of prey from Tetraponera aethiops Smith (Formicidae; Pseudomyrmecinae) specifically associated with Barteria fistulosa Mast. (Passifloraceae). (2) Charterginus spp. (Epiponini) rob food bodies from myrmecophytic Cecropia (Cecropiaceae) exploited by their Azteca mutualists (Formicidae; Dolichoderinae) or by opportunistic ants (that also attack cleptobiotic wasps). We note here that
wasps gather food bodies (1) when ants are not yet active; (2) when ants are active, but avoiding any contact with them by
flying off when attacked; and (3) through the coordinated efforts of two to five wasps, wherein one of them prevents the ants
from leaving their nest, while the other wasps freely gather the food bodies. We suggest that these interactions are more
common than previously thought. 相似文献