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1.
A gall midge that induces thick lenticular galls on leaflets of Pueraria species (Fabaceae) in Japan, mainland China, Taiwan and South Korea is described as Pitydiplosis puerariae sp. nov. (Diptera: Cecidomyiidae). Tanaostigmodes puerariae (Hymenoptera: Tanaostigmatidae), described earlier from mainland China as an inducer of the lenticular gall, is regarded to be an inquiline. Pitydiplosis puerariae is distinguishable from the only known congener, the Nearctic Pitydiplosis packardi, by the male genitalia with entire aedeagus and with hypoproct that is as long as cerci and bilobed with a U‐shaped emargination. DNA sequencing data indicate the existence of three genetically different intraspecific groups: (i) “YNT‐montana group” induces galls on Pueraria montana on the Yaeyama Islands, Japan and in northern Taiwan; (ii) “CT‐montana group” on P. montana in central Taiwan; (iii) and “JCK‐lobata group” on Pueraria lobata in mainland China, South Korea and Japan north of Okinoerabu Island. A possible diversification scenario of the three groups is hypothesized based on DNA sequencing data and geohistorical information. A distribution gap of the gall midge on five islands between Tokunoshima and Ishigaki Islands, Japan was confirmed by intensive field surveys. Ecological traits and adult behavior of Pity. puerariae are also described. Its possibility as a potential biological control agent against P. lobata seems counter‐indicated.  相似文献   

2.
1. The evolution of eusociality in Australian gall‐inducing thrips cannot be understood without comparisons among closely related solitary species. The life history of two solitary, gall‐inducing thrips, Kladothrips ellobus and Oncothrips rodwayi, was investigated, and data for solitary and eusocial species from previous studies were re‐analysed. Kladothrips ellobus is in a clade that is closely related to the eusocial species. Oncothrips rodwayi is in the same clade as the eusocial species and appears to have undergone an evolutionary loss of eusociality. It is the only galling thrips on Acacia in temperate environments. 2. The brood size of K. ellobus is eight to 23 times larger than broods of foundresses in eusocial species whereas the brood size of O. rodwayi is not significantly different from those of foundresses in eusocial species. 3. In K. ellobus, the mean sex ratio was not significantly different from parity but in O. rodwayi the mean sex ratio was 0.13 male. In O. rodwayi, 77% of females were inseminated by their brothers before dispersal, which is consistent with high levels of inbreeding in eusocial species of the same clade. Sex ratios suggest random mating in K. ellobus whereas female‐biased sex ratios in O. rodwayi are consistent with inbreeding and local mate competition. 4. Comparisons among solitary and eusocial species suggest that large brood size is an ancestral trait for eusociality in thrips, and this trait persists in solitary species as an r‐selection strategy. Soldiers may have evolved in arid environments to minimise the risks of dispersal and the costs of latency to reproduction, and to maximise gall defence. 5. Temperate conditions could have facilitated the evolutionary loss of soldiers in O. rodwayi, as there should be a shorter, safer, more predictable window period between dispersal and gall induction, reducing the period of latency to reproduction following dispersal and lowering risks of dispersal. 6. The loss of soldiers in O. rodwayi is not associated with a reversion to the large brood sizes of solitary species in ancestral lineages.  相似文献   

3.
1. Herbivorous insects often have close associations with specific host plants, and their preferences for mating and ovipositing on a specific host‐plant species can reproductively isolate populations, facilitating ecological speciation. Volatile emissions from host plants can play a major role in assisting herbivores to locate their natal host plants and thus facilitate assortative mating and host‐specific oviposition. 2. The present study investigated the role of host‐plant volatiles in host fidelity and oviposition preference of the gall‐boring, inquiline beetle, Mordellistena convicta LeConte (Coleoptera: Mordellidae), using Y‐tube olfactometers. Previous studies suggest that the gall‐boring beetle is undergoing sequential host‐associated divergence by utilising the resources that are created by the diverging populations of the gall fly, Eurosta solidaginis Fitch (Diptera: Tephritidae), which induces galls on the stems of goldenrods including Solidago altissima L. (Asteraceae) and Solidago gigantea Ait. 3. Our results show that M. convicta adults are attracted to galls on their natal host plant, avoid the alternate host galls, and do not respond to volatile emissions from their host‐plant stems. 4. These findings suggest that the gall‐boring beetles can orient to the volatile chemicals from host galls, and that beetles can use them to identify suitable sites for mating and/or oviposition. Host‐associated mating and oviposition likely play a role in the sequential radiation of the gall‐boring beetle.  相似文献   

4.
Gall formation is a specialised form of phytophagy that consists of abnormal growth of host plant tissue induced by other organisms, principally insects and mites. In the mainly parasitoid wasp subfamily Doryctinae, gall association, represented by gall inducers, inquilines and their parasitoids, is known for species of seven genera. Previous molecular studies recovered few species of six of these genera as monophyletic despite their disparate morphologies. Here, we reconstructed the evolutionary relationships among 47 species belonging to six gall‐associated doryctine genera based on two mitochondrial and two nuclear gene markers. Most of the Bayesian analyses, performed with different levels of incomplete taxa and characters, supported the monophyly of gall‐associated doryctines, with Heterospilus (Heterospilini) as sister group. Percnobracon Kieffer and Jörgensen and Monitoriella Hedqvist were consistently recovered as monophyletic, and the validity of the monotypic Mononeuron was confirmed with respect to Allorhogas Gahan. A nonmonophyletic Allorhogas was recovered, although without significant support. The relationships obtained and the gathered morphological and biological information led us to erect three new genera originally assigned to Psenobolus: Ficobolus gen.n. (F. paniaguai sp.n. and F. jaliscoi sp.n. ), Plesiopsenobolus gen.n. (Pl. mesoamericanus sp.n. , Pl. plesiomorphus van Achterberg and Marsh comb.n. , and Pl. tico sp.n. ), and Sabinita gen.n. (S. mexicana sp.n. ). The origin of the gall‐associated doryctine clade was estimated to have occurred during the middle Miocene to early Oligocene, 16.33–30.55 Ma. Our results support the origin of true gall induction in the Doryctinae from parasitoidism of other gall‐forming insects. Moreover, adaptations to attack different gall‐forming taxa on various unrelated plant families probably triggered species diversification in the main Allorhogas clade and may also have promoted the independent origin of gall formation on at least three plant groups. Species diversification in the remaining doryctine taxa was probably a result of host shifts within a particular plant taxon and shifts to different plant organs. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:0021F253‐4ABA‐4EAA‐A7A9‐FC0AD1932EA3  相似文献   

5.
Most hypotheses to explain nonrandom mating patterns invoke mate choice, particularly in species that display elaborate ornaments. However, conflicting selection pressures on traits can result in functional constraints that can also cause nonrandom mating patterns. We tested for functional load‐lifting constraints during aerial copulation in Rhamphomyia longicauda, a species of dance fly that displays multiple extravagant female‐specific ornaments that are unusual among sexual traits because they are under stabilizing selection. R. longicauda males provide females with a nuptial gift before engaging in aerial mating, and the male bears the entire weight of the female and nuptial gift for the duration of copulation. In theory, a male's ability to carry females and nuptial gifts could constrain pairing opportunities for the heaviest females, as reported for nonornamented dance flies. In concert with directional preferences for large females with mature eggs, such a load‐lifting constraint could produce the stabilizing selection on female size previously observed in this species. We therefore tested whether wild‐caught male R. longicauda collected during copulation were experiencing load‐lift limitations by comparing the mass carried by males during copulation with the male's wing loading traits. We also performed permutation tests to determine whether the loads carried by males during copulation were lighter than expected. We found that heavier males are more often found mating with heavier females suggesting that whereas R. longicauda males do not experience a load‐lift constraint, there is a strong relationship of assortative mating by mass. We suggest that active male mate choice for intermediately adorned females is more likely to be causing the nonrandom mating patterns observed in R. longicauda.  相似文献   

6.
Gall midges of the genus Contarinia (Diptera: Cecidomyiidae) that infest the flower buds of various plant species have been newly found in Japan in recent years. Those infesting the flower buds of Pseuderanthemum laxiflorum (A. Gray) Hubbard ex Baillon (Amaranthaceae) and Jasminum sambac (Linnaeus) Aiton (Oleaceae) in Okinawa Prefecture, and Dendrobium spp. (Orchidaceae) in Mie Prefecture were identified, on the basis of morphological features and molecular information, as an invasive gall midge, C. maculipennis Felt. C. maculipennis was recorded in Mie Prefecture for the first time, and P. laxiflorum is newly regarded as one of the host plants of C. maculipennis. Three other Contarinia gall midges that we found infesting the flower buds of Lycopersicon esculentum Miller, Capsicum annuum Linnaeus (Solanaceae), and Oxalis corniculata Linnaeus (Oxalidaceae) were not identical with C. maculipennis. Among these, the first two, which infested solanaceous plants, were identical. However, the species other than C. maculipennis could not be identified to the species level because morphological differences were obscure and DNA sequencing data of allied congeners have not yet been registered on GenBank.  相似文献   

7.
The genus Rqfflesia includes about 13 species of parasitic flowering plants, among which are the largest known flowers. The flower with subtending scales is the only part of the plant external to the host and is produced solitary on roots (rarely stems) of the genus Tetrastigma (Vitaceae). Field studies were made of the pollination process in R. pricei, a species endemic to the Crocker Range in the Malaysian state of Sabah (northern Borneo). Pollination is mediated by carrion (bluebottle) flies of the genera Lucilla and Chrysomya. Experimental data indicate that both visual and olfactory cues are important in attracting flies to flowers. Flies (mostly female L. papuensis) obtain loads of the viscous liquid pollen matrix by visiting male flowers and entering anther grooves on the central column of the flower, precisely guided by ridges armed with hairs that force the fly into a position in which the pollen is positioned on the dorsal part of the thorax. “Windows” on the inside of the perigone diaphragm apparently help orient their flight inside flowers. Pollen-loaded flies visiting female flowers may enter the infradiscoidal sulcus formed by a broad ring of stigmatic tissue above and the expanded base of the column below. On entering the sulcus the fly is wedged in so tightly that pollen is rubbed off the thorax onto the stigma. Only large flies could be effective in picking up pollen from male flowers and transferring it to female flowers. The pollination syndrome is sapromyophily, in which the flower closely parallels trap flowers of several other plant families, although it is not a trap. The flower provides no reward for pollinators but deceives them by an apparent offering of food and possibly brood place. Rafflesia plants are extremely rare, perhaps in part because of infrequency of pollination, which requires neighboring male and female flowers simultaneously in bloom.  相似文献   

8.
In the past, Rhopalomyia longitubifex, Rhopalomyia shinjii, and Rhopalomyia sp. (Diptera: Cecidomyiidae) have been regarded as independent species based on differences in the sizes and shapes of axillary bud galls induced on Artemisia montana (Asteraceae) in Japan and A. princeps in Japan and Korea. However, comparison of morphological features and molecular sequencing data indicate that these Rhopalomyia gall midges are identical and that the differences in gall shape are polymorphisms, although the measurements of gall height and diameter overlap slightly. This finding suggests that although galls have frequently been regarded as extensions of the phenotype of a species, differences in gall shape may not always be reliable for identifying gall‐inducing cecidomyiids. The older name, R. longitubifex, is applied to these gall midges, and the names that were applied to this species on later occasions are revised or synonymized. The mature and immature stages of R. longitubifex are redescribed and information on the distribution, host range, and gall size of this species is provided. We also discuss the role of gall polymorphism in the early stages of speciation.  相似文献   

9.
Floral nectaries are closely associated with biotic pollination, and the nectar produced by corolla nectaries is generally enclosed in floral structures. Although some Swertia spp. (Gentianaceae), including S. bimaculata, evolved a peculiar form of corolla nectaries (known as “gland patches”) arranged in a conspicuous ring on the rotate corolla and that completely expose their nectar, little is known about the pollination of these plants. Two hypotheses were made concerning the possible effects of gland patches: visual attraction and visitor manipulation. The floral traits, mating system, and insect pollination of S. bimaculata were examined, and the pollination effects of gland patches were evaluated. A comparative study was made using Swertia kouitchensis, a species with fimbriate nectaries. Swertia bimaculata flowers were protandrous, with obvious stamen movement leading to herkogamy in the female phase and to a significant reduction in nectary–anther distance. The species is strongly entomophilous and facultatively xenogamous. The daily reward provided per flower decreased significantly after the male phase. The most effective pollinators were large dipterans, and the visiting proportion of Diptera was significantly higher in S. bimaculata than in S. kouitchensis. Most visitors performed “circling behavior” in S. bimaculata flowers. Removing or blocking the nectaries caused no reduction in visiting frequency but a significant reduction in visit duration, interrupting the circling behavior. The circling behavior was encouraged by nectar abundance and promoted pollen dispersal. Visitor species with small body size had little chance to contact the anthers or stigma, revealing a filtration effect exerted by the floral design. These results rejected the “visual attraction” hypothesis and supported the “visitor manipulation” hypothesis. The nectary whorl within a flower acted like a ring‐shaped track that urged nectar foragers to circle on the corolla, making pollination in S. bimaculata flowers more orderly and selective than that in classically generalist flowers.  相似文献   

10.
The role of pollinators in floral divergence has long attracted the attention of evolutionary biologists. Although abundant studies have reported the effect of pollinators on flower‐shape variation and plant speciation, the influence of pollinators on plant species differentiation during rapid radiations and the specific consequences of shifts among similar pollinators are not well understood. Here, we evaluate the association between pollinators and floral morphology in a closely related and recently diversifying clade of Linaria species (sect. Supinae subsect. Supinae). Our approach combined pollinator observations, functional floral morphometric measures and phylogenetic comparative analyses. The fauna visiting Linaria species was determined by extensive surveys and categorized by a modularity algorithm, and the size and shape of flowers were analysed by means of standard and geometric morphometric measures. Standard measures failed to find relationships between the sizes of representative pollinators and flowers. However, discriminant function analyses of geometric morphometric data revealed that pollination niches are finer predictors of flower morphologies in Linaria if compared with phylogenetic relationships. Species with the most restrictive flowers displayed the most slender spurs and were pollinated by bees with larger proboscides. These restrictive flower shapes likely appeared more than once during the evolutionary history of the study group. We show that floral variation can be driven by shifts between pollinators that have been traditionally included in a single functional group, and discuss the consequences of such transitions for plant species differentiation during rapid radiations.  相似文献   

11.
Characterizing the mating systems of long‐lived, economically important Pacific rockfishes comprising the viviparous Sebastes species flock is crucial for their conservation. However, direct assignment of mating success to sires is precluded by open, offshore populations and high female fecundity. We addressed this challenge by integrating paternity‐assigned mating success of females with the adult sex ratio (ASR) of the population, male evolutionary responses to receptive females, and reproductive life history traits—in the framework of sexual selection theory—to assess the mating system of Sebastes melanops. Microsatellite parentage analysis of 17 pregnant females, 1,256 of their progeny, and 106 adults from the population yielded one to four sires per brood, a mean of two sires, and a female mate frequency distribution with a truncated normal (random) pattern. The 11 multiple paternity broods all contained higher median allele richness than the six single paternity broods (Wilcoxon test: W = 0, p < .001), despite similar levels of average heterozygosity. By sampling sperm and alleles from different males, polyandrous females gain opportunities to enhance their sperm supply and to lower the cost of mating with genetically incompatible males through reproductive compensation. A mean of two mates per mated female with a variance of one, an ASR = 1.2 females per male, and the expected population mean of 2.4 mates for mated males (and the estimated 35 unavailable sires), fits polygamous male mate frequency distributions that distinguish polygynandry and polyandrogyny mating systems, that is, variations of polygamy, but not polyandry. Inference for polygamy is consistent with weak premating sexual selection on males, expected in mid‐water, schooling S. melanops, owing to polyandrous mating, moderately aggregated receptive females, an even ASR, and no territories and nests used for reproduction. Each of these characteristics facilitates more mating males and erodes conspicuous sexual dimorphism. Evaluation of male evolutionary responses of demersal congeners that express reproductively territorial behavior revealed they have more potential mechanisms for producing premating sexual selection, greater variation in reproductive success, and a reduced breeding effective population size of adults and annual effective size of a cohort, compared to S. melanops modeled with two mates per adult. Such divergence in behavior and mating system by territorial species may differentially lower their per capita birth rates, subsequent population growth, and slow their recovery from exploitation.  相似文献   

12.
The morphology and morphogenesis of a new soil hypotrich ciliate, Sterkiella multicirrata sp. nov., was investigated using live observation and protargol staining. The new species is characterised by: body elliptical, 110–180 × 45–75 μm in vivo, an average of 35 adoral membranelles; usually 19 frontoventral‐transverse cirri, consisting of three frontal, five frontoventral, one buccal, four postoral ventral, two pretransverse, and four transverse cirri; four macronuclear nodules, and 2–5 micronuclei. S. multicirrata sp. nov. differs from its congeners mainly in the number of frontoventral‐transverse cirri and macronuclear nodules. Morphogenesis of the new species is similar to its congeners; the primary difference exists in the segmentation of the frontoventral‐transverse cirral anlagen, which is usually generated in a 1:2:3:3:5:5 pattern. Based on the small subunit ribosomal DNA sequence, the phylogenetic position of the new species is discussed.  相似文献   

13.
The morphology, infraciliature, and molecular phylogeny of two novel spirotrich ciliates, Caryotricha rariseta n. sp. and Discocephalus pararotatorius n. sp., isolated from coastal waters of China, were investigated. Caryotricha rariseta n. sp. differs from its congeners mainly in possessing seven sparsely ciliated cirral rows that are conspicuously shortened posteriorly and three transverse cirri aligned in a row. Discocephalus pararotatorius n. sp. is characterized by the conspicuous spine‐like dorsal cilia, one extra (endoral?) membrane, and seven frontal, six ventral, and seven posterolateral marginal cirri. The small subunit rRNA gene was sequenced for both species. Complete SSU rRNA gene sequences of two Caryotricha spp. (including C. rariseta n. sp.) and two Discocephalus spp. (including D. pararotatorius n. sp.), along with those of 40 other ciliates, were used to determine their molecular phylogeny using maximum likelihood, neighbor joining and maximum parsimony analyses. The two Caryotricha species cluster with Kiitricha marina in the well‐supported Protohypotrichia clade that is basal to the main spirotrich assemblage. The two discocephalids form a clade that is sister to the Hypotrichia.  相似文献   

14.
Haplodiploidy is a highly unusual genetic system that has arisen at least 17 times in animals of varying lifestyles, but most of these haplodiploid lineages remain relatively poorly known. In particular, the ecological and genetic circumstances under which haplodiploidy originates have been difficult to resolve. A recent molecular‐phylogenetic study has resolved the phylogenetic position of the haplodiploid clade of scolytine beetles as the sister group of the genus Dryocoetes. Haplodiploid bark beetles are remarkable in that the entire clade of over 1300 species are apparently extreme (sib‐mating) inbreeders, most of which cultivate fungi for food while some attack phloem, twigs or seeds. Here we present a much more detailed molecular‐phylogenetic study of this clade. Using partial sequences of elongation factor 1‐alpha and the mitochondrial small ribosomal subunit (12S), we reconstructed the phylogeny for 48 taxa within the haplodiploid clade, as well as two species of the diplodiploid sister genus Dryocoetes. Results indicate that the genus Ozopemon is the basal lineage of die haplodiploid clade. Since Ozopemon, Dryocoetes, and other outgroups are phloem‐feeding, this strongly suggest that haplodiploidy and inbreeding evolved in a phloem feeding ancestor. Following the divergence of Ozopemon there is a series of extremely short internodes near the base of the clade, suggesting a very rapid rate of diversification in early Miocene (based on fossil evidence and sequence divergence). Among the many substrates for breeding and food resources utilized within this species‐rich clade, the cultivation of yeast‐like ambrosia fungi in tunnels deep into the wood predominates (nearly 90% of the species). The number of transitions to feeding on such fungi was few, possibly only one, and is perhaps an irreversible transition. The habit of feeding on fungi cultured in xylem makes it possible for the beetles to use a great variety of plant taxa. This extreme resource generalism, in conjunction with the colonization advantage conferred by haplodiploidy and inbreeding, may have promoted the rapid diversification of this clade.  相似文献   

15.
Six species of gall midge are described from Australian acacias. Asphondylia bursicola Kolesik sp.n. and A. occidentalis Kolesik sp.n . form galls on fruit; A. germinis Kolesik sp.n ., A. pilogerminis Kolesik sp.n . and A. glabrigerminis Kolesik sp.n . induce severe deformation of flower buds; and A. acaciae Kolesik sp.n . causes galls on both fruit and flower buds. Galled flower buds do not produce flowers, and galled fruit produce no or undeveloped seeds. Host ranges of the new species comprise between two and eight acacia hosts. Larval, pupal and male morphology, together with phylogenetic analyses of a 410‐bp fragment of the mitochondrial cytochrome b gene, were used to characterize the new species. For A. bursicola, A. germinis, A. pilogerminis, A. glabrigerminis and A. acaciae, the intraspecific divergence values were between 0.2 and 3.4%, and the interspecific divergence values ranged between 5.1 and 10.5%. For A. occidentalis, the only species with geographical distribution confined solely to Western Australia, the intraspecific divergence was between 6.6 and 10.3%, and the interspecific difference from the other five new species was between 9.3 and 13.9%. In contrast to Dasineura spp. from Acacia, for which the morphology was more informative in species recognition than the cytochrome b sequence, in Asphondylia spp. treated here the partial cytochrome b sequence data provided better species recognition than did the morphology. Several of the new Asphondylia have potential as biological control agents in ecosystems in which Australian acacias are invasive and their sexual reproduction needs to be restricted. A list of Australian acacias whose reproductive organs are destroyed by known gall midges, all belonging to Dasineura and Asphondylia, is provided.  相似文献   

16.
Behavioral interactions among color-marked individual Vidua chalybeata that shared common song dialects were observed for 5 years in two populations at Lochinvar National Park, Zambia. Social interactions involved ♂♂ visiting and competing for mating sites and ♀♀ visiting ♂♂ in an apparent sampling of potential copulating partners. Differences in mating success among the polygynous ♂♂ were compared with male behavior and territory resources, and criteria were developed to test the importance of intrasexual male competition and female mate choice in explaining the mating system of the populations. Song behavior best explained differences in mating success of ♂♂ with lesser effects of neighboring ♂♂ and the defensible resources around the call-sites. The social organization of song populations resembles that of a dispersed lek with ♀♀ visiting many ♂♂ but mating with few ♂♂. We discuss the observations on indigobirds in relation to behavioral selection, sexual selection, and mating systems. Mating systems of certain populations and species are compared using statistics of individual mating success.  相似文献   

17.
Fates and growth of Rafflesia patma buds and insect visitation to the flowers were monitored in an evergreen tropical rain forest in the Pangandaran Nature Reserve, Java, Indonesia, Of 59 buds marked in December 1985, 44 percent died before flowering, 7 percent flowered, and 49 percent were still in bud in May 1986. Mammals and birds caused the deaths of buds before they reached maturity. Only four buds flowered between December 1985 and May 1986; all were male. Rate of increase in diameter (cm/d) was much faster in large than in small buds. Once opening began, the flower opened fully in 24 to 48 hours; the flower remained open for three to five days before rotting. Only two genera of insects visited a male flower of R. patma: Lucilia and Sarcophaga (Diptera). Insect visitation was highest in the afternoon (1300–1700 h) and on the second or third day after flower opening. The increased number of flies visiting the flower coincided with the increasing odor emitted from it. Results of the present study were combined with information from the literature to construct a life cycle diagram of R. patma.  相似文献   

18.
In ecosystems with seasonal fluctuations in food supply many species use two strategies to store food: larder hoarding and scatter hoarding. However, because species at different geographic locations may experience distinct environmental conditions, differences in hoarding behavior may occur. Tree squirrels in the genus Tamiasciurus display variation in hoarding behavior. Whereas red (Tamiasciurus hudsonicus) and Douglas's (Tamiasciurus douglasii) squirrels in mesic coniferous forests defend territories centered around larder hoards maintaining non‐overlapping home ranges, red squirrels in deciduous forests defend small scatter‐hoarded caches of cones maintaining overlapping home ranges. As in other rodent species, variation in hoarding behavior appears to influence the spacing behavior of red and Douglas's squirrels. In contrast, Mearns's squirrels (Tamiasciurus mearnsi) in xeric coniferous forests neither rely on larder hoards nor appear to display territorial behavior. Unfortunately, little is known about the ecology of this southernmost Tamiasciurus. Using radiotelemetry, we estimated home‐range size, overlap, and maximum distance traveled from nest to examine the spacing behavior of Mearns's squirrels. Similar to scatter‐hoarding rodents, maximum distance traveled from nest was greater for males during mating season, whereas those of females were similar year round. Although no seasonal differences were detected, male home ranges were three times larger during mating season, whereas those of females were smaller and displayed a minor variation between seasons. Home ranges were overlapped year round but contrary to our expectations, overlap was greater during mating season for both sexes, with no detectable relationship between male home‐range size and the number of females overlapped during mating season. Overall, the results appear to support our hypothesis that in the absence of larder hoards, the spacing behavior of Mearns's squirrels should be different from larder‐hoarding congeners and more similar to scatter‐hoarding rodents.  相似文献   

19.
Pollinator morphology can play an important role in structuring plant–pollinator relationships and a pollinator's morphology may be associated with aspects of its diet. We examined the relationship between morphology and the partitioning of flower‐based food resources for five species of flower‐visiting Cuban bats: Artibeus jamaicensis, Brachyphylla nana, Erophylla sezekorni, Monophyllus redmani and Phyllonycteris poeyi. We analyzed cranial traits and body size to assess differences among species with respect to morphological specializations. We also collected dietary data from guano and used acoustic monitoring to assess bat activity at flowers. We found evidence that bats partition floral resources, but we found no direct evidence that plants were limiting resources for the bats. Morphological similarity among bat species did not predict dietary overlap. Rather it was associated with phylogenic relationships among some species. Species with different morphological specialization for flower‐visiting consumed resources and visited food plants at different frequencies.  相似文献   

20.
Androdioecy was first described by Darwin in his seminal work on barnacle diversity; he identified males and hermaphrodites in the same reproductive population. Today, we realize that many androdioecious plants and animals share astonishing similarities, particularly with regard to their evolutionary history and mating system. Notably, these species were ancestrally dioecious, and their mating system has the following characteristics: hermaphrodites self‐fertilize frequently, males are more successful in large mating groups, and males have a mating advantage. A male mating advantage makes androdioecy more likely to persist over evolutionary times. Androdioecious barnacles, however, appear to persist as an outlier with a different evolutionary trajectory: they originate from hermaphroditic species. Although sexual systems of androdioecious barnacles are known, no information on the mating system of androdioecious barnacles is available. This study assessed the mating system of the androdioecious barnacle Chelonibia testudinaria. In contrast to other androdioecious species, C. testudinaria does not self‐fertilize, males do not have a mating advantage over hermaphrodites, and the average mating group is quite small, averaging only three individuals. Mating success is increased by proximity to the mate and penis length. Taken together, the mating system of C. testudinaria is unusual in comparison with other androdioecious plants and animals, and the lack of a male mating advantage suggests that the mating system alone does not provide an explanation for the maintenance of androdioecy in this species. Instead, we propose that sex‐specific life history equalizes male and hermaphroditic overall fitness.  相似文献   

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