146 research outputs found
Assessment of pollen rewards by foraging bees
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.The removal of pollen by flower-visiting insects is costly to plants, not only in
terms of production, but also via lost reproductive potential. Modern
angiosperms have evolved various reward strategies to limit these costs, yet
many plant species still offer pollen as a sole or major reward for pollinating
insects.
2. The benefits plants gain by offering pollen as a reward for pollinating are
defined by the behaviour of their pollinators, some of which feed on the pollen
at the flower, while others collect pollen to provision offspring.
3. We explore how pollen impacts on the behaviour and foraging decisions of
pollen-collecting bees, drawing comparisons with what is known for nectar
rewards. This question is of particular interest since foraging bees typically do
not ingest pollen during collection, meaning the sensory pathways involved in
evaluating this resource are not immediately obvious.
4. Previous research focussed on whether foraging bees can determine the quality
of pollen sources offered by different plant species, and attempted to infer the
mechanisms underpinning such evaluations, mainly through observations of
collection preferences in the field
5. More recent experimental research has started to focus on if pollen itself can
mediate the detection of, and learning about, pollen sources and associated
floral cues.
6. We review advancements in the understanding of how bees forage for pollen
and respond to variation in pollen quality, and discuss future directions for
studying how this ancestral floral food reward shapes the behaviour of
pollinating insects
A simple and distinctive microbiota exclusively associated with honey bees and bumble bees
Abstract: Specialized relationships with bacteria often allow animals to exploit a new diet by providing a novel set of metabolic capabilities. Bees are a monophyletic group of Hymenoptera that transitioned to a completely herbivorous diet from the carnivorous diet of their wasp ancestors. Recent culture-independent studies suggest that a set of distinctive bacterial species inhabits the gut of the honey bee, Apis mellifera. Here we survey the gut microbiotae of diverse bee and wasp species to test whether acquisition of these bacteria was associated with the transition to herbivory in bees generally. We found that most bee species lack phylotypes that are the same or similar to those typical of A. mellifera, rejecting the hypothesis that this dietary transition was symbiont-dependent. The most common bacteria in solitary bee species are a widespread phylotype of Burkholderia and the pervasive insect associate, Wolbachia. In contrast, several social representatives of corbiculate bees do possess distinctive bacterial phylotypes. Samples of A. mellifera harboured the same microbiota as in previous surveys, and closely related bacterial phylotypes were identified in two Asian honey bees (Apis andreniformis and Apis dorsata) and several bumble bee (Bombus) species. Potentially, the sociality of Apis and Bombus species facilitates symbiont transmission and thus is key to the maintenance of a more consistent gut microbiota. Phylogenetic analyses provide a more refined taxonomic placement of the A. mellifera symbionts. apis mellifera | bacterial microbiota | insect symbiosis | microbiology | molecula
Predicting invasions of North American basses in Japan using native range data and a genetic algorithm
Largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu have been
introduced into freshwater habitats in Japan, with potentially serious consequences for native fish
populations. In this paper we apply the technique of ecological niche modeling using the genetic
algorithm for rule-set prediction (GARP) to predict the potential distributions of these two species
in Japan. This algorithm constructs a niche model based on point occurrence records and ecological
coverages. The model can be visualized in geographic space, yielding a prediction of potential
geographic range. The model can then be tested by determining how well independent point
occurrence data are predicted according to the criteria of sensitivity and specificity provided by
receiver–operator curve analysis. We ground-truthed GARP’s ability to forecast the geographic
occurrence of each species in its native range. The predictions were statistically significant for
both species (P , 0.001). We projected the niche models onto the Japanese landscape to visualize
the potential geographic ranges of both species in Japan. We tested these predictions using known
occurrences from introduced populations of largemouth bass, both in the aggregate and by habitat
type. All analyses robustly predicted known Japanese occurrences (P , 0.001). The number of
smallmouth bass in Japan was too small for statistical tests, but the 10 known occurrences were
predicted by the majority of models
Complex evolutionary history of the Mexican stoneroller Campostoma ornatum Girard, 1856 (Actinopterygii: Cyprinidae)
<p>Abstract</p> <p>Background</p> <p>Studies of the phylogeography of Mexican species are steadily revealing genetic patterns shared by different species, which will help to unravel the complex biogeographic history of the region. <it>Campostoma ornatum </it>is a freshwater fish endemic to montane and semiarid regions in northwest Mexico and southern Arizona. Its wide range of distribution and the previously observed morphological differentiation between populations in different watersheds make this species a useful model to investigate the biogeographic role of the Sierra Madre Occidental and to disentangle the actions of Pliocene tecto-volcanic processes <it>vs </it>Quaternary climatic change. Our phylogeographic study was based on DNA sequences from one mitochondrial gene (<it>cytb</it>, 1110 bp, n = 285) and two nuclear gene regions (S7 and RAG1, 1822 bp in total, n = 56 and 43, respectively) obtained from 18 to 29 localities, in addition to a morphological survey covering the entire distribution area. Such a dataset allowed us to assess whether any of the populations/lineages sampled deserve to be categorised as an evolutionarily significant unit.</p> <p>Results</p> <p>We found two morphologically and genetically well-differentiated groups within <it>C. ornatum</it>. One is located in the northern river drainages (Yaqui, Mayo, Fuerte, Sonora, Casas Grandes, Santa Clara and Conchos) and another one is found in the southern drainages (Nazas, Aguanaval and Piaxtla). The split between these two lineages took place about 3.9 Mya (CI = 2.1-5.9). Within the northern lineage, there was strong and significant inter-basin genetic differentiation and also several secondary dispersal episodes whit gene homogenization between drainages. Interestingly, three divergent mitochondrial lineages were found in sympatry in two northern localities from the Yaqui river basin.</p> <p>Conclusions</p> <p>Our results indicate that there was isolation between the northern and southern phylogroups since the Pliocene, which was related to the formation of the ancient Nazas River paleosystem, where the southern group originated. Within groups, a complex reticulate biogeographic history for <it>C. ornatum </it>populations emerges, following the taxon pulse theory and mainly related with Pliocene tecto-volcanic processes. In the northern group, several events of vicariance promoted by river or drainage isolation episodes were found, but within both groups, the phylogeographic patterns suggest the occurrence of several events of river capture and fauna interchange. The Yaqui River supports the most diverse populations of <it>C. ornatum</it>, with several events of dispersal and isolation within the basin. Based on our genetic results, we defined three ESUs within <it>C. ornatum </it>as a first attempt to promote the conservation of the evolutionary processes determining the genetic diversity of this species. They will likely be revealed as a valuable tool for freshwater conservation policies in northwest Mexico, where many environmental problems concerning the use of water have rapidly arisen in recent decades.</p
Signalling plasticity and energy saving in a tropical bushcricket
Males of the tropical bushcricket Mecopoda elongata synchronize their acoustic advertisement signals (chirps) in interactions with other males. However, synchrony is not perfect and distinct leader and follower roles are often maintained. In entrainment experiments in which conspecific signals were presented at various rates, chirps displayed as follower showed notable signal plasticity. Follower chirps were shortened by reducing the number and duration of syllables, especially those of low and medium amplitude. The degree of shortening depended on the time delay between leader and follower signals and the sound level of the entraining stimulus. The same signal plasticity was evident in male duets, with the effect that the last syllables of highest amplitude overlapped more strongly. Respiratory measurements showed that solo singing males producing higher chirp rates suffered from higher metabolic costs compared to males singing at lower rates. In contrast, respiratory rate was rather constant during a synchronous entrainment to a conspecific signal repeated at various rates. This allowed males to maintain a steady duty cycle, associated with a constant metabolic rate. Results are discussed with respect to the preference for leader signals in females and the possible benefits males may gain by overlapping their follower signals in a chorus
Qualificação e quantificação da exposição sonora ambiental em uma unidade de terapia intensiva geral
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