Saltmarsh vegetation and social environment influence flexible seasonal vigilance strategies for two sympatric migratory curlew species in adjacent coastal habitats

Background:Animals need to adjust their vigilance strategies when foraging between physically contrasting veg-etated and non-vegetated habitats.Vegetated habitats may pose a greater risk for some if vegetation characteristics function as a visual obstruction but benefit others if they serve as protective shelter.Variation in group size,presence of similar species,along with variation in environmental conditions and anthropogenic disturbance can also influence vigilance investment.Methods:In this study,we quantified the vigilance behaviour of two large-bodied,sympatric migratory curlew species-Far Eastern Curlew(Numenius madagascariensis)and Eurasian Curlew(N.arquata)-in vegetated Suaeda salsa saltmarsh and non-vegetated mudflat habitat in Liaohekou National Nature Reserve,China.We used linear mixed models to examine the effects of habitat type,season,tide time,flock size(conspecific and heterospecific),and human disturbance on curlew vigilance investment.Results:Both species spent a higher percentage of time under visual obstruction in S.salsa habitat compared to mudflat habitat but in response,only Far Eastern Curlew increased their percentage of vigilance time,indicating that visual obstruction in this habitat is only a concern for this species.There was no evidence that S.salsa vegetation served as a form of cryptic background colouration since neither species decreased their vigilance effect in S.salsa habitat in spring compared to the autumn migration season.The effect of curlew social environment(i.e.flock size)was habitat dependent since percentage of vigilance time by curlews in saltmarsh increased with both the number of individual curlews and number of other birds present,but not in mudflat habitat.Conclusions:We conclude that both migratory curlew species exhibit a flexible vigilance adjustment strategy to cope with the different environmental and social conditions of adjacent and sharply contrasting coastal habitats,and that the trade-off between the risks of foraging and the abundance of prey may be a relatively common phenom-enon in these and other shorebird populations.

Which species discovers novel food sources first?A camera trap study in a natural environment

Birds underlie a predation-starvation risk,and foraging should show a diurnal/circadian pattern.Camera traps were used to study visitation patterns and discovery of a novel food source in woodland birds in SW Germany.A total of 18 species occurred at feeders with nine of them being exploratory species.Great Tits(Parus major)discovered novel food sources first in most instances,and first discoveries occurred on average at 10:38,while it took 97 h for the first detection of the food source.Population size was correlated with discovery.The study supports the predation-starva-tion risk hypothesis with discovery of food sources in the morning.

Sugar concentration influences decision making in Apis mellifera L.workers during early-stage honey storage behaviour

Decision making in honeybees is based on information which is acquired and processed in order to make choices between two or more alternatives. These choices lead to the expression of optimal behaviour strategies such as floral constancy. Optimal foraging strategies such as floral constancy improve a colony’s chances of survival, however to our knowledge, there has been no research on decision making based on optimal storage strategies. Here we show, using diagnostic radioentomology, that decision making in storer bees is influenced by nectar sugar concentrations and that, within 48 hours of collection, honeybees workers store carbohydrates in groups of cells with similar sugar concentrations in a nonrandom way. This behaviour, as evidenced by patchy spatial cell distributions, would help to hasten the ripening process by reducing the distance between cells of similar sugar concentrations. Thus, colonies which exhibit optimal storage strategies such as these would have an evolutionary advantage and im- prove colony survival expectations over less efficient colonies and it should be plausible to select colonies that exhibit these preferred traits.

Evaluating Behavioural Modelling Predictions in the Blue Shark (Prionace glauca) Enables Greater Insight on Habitat Use from Location only Argos Data

The relationship between habitat and behaviour provides important information for species management.For large,free roaming,marine animals satellite tags provide high resolution information on movement,but such datasets are restricted due to cost.Extracting additional biologically important information from these data would increase utilisation and value.Several modelling approaches have been developed to identify behavioural states in tracking data.The objective of this study was to evaluate a behavioural state prediction model for blue shark(Prionace glauca)ARGOS surface location-only data.The novel nature of the six SPLASH satellite tags used enabled behavioural events to be identified in blue shark dive data and accurately mapped spatio-temporally along respective surface location-only tracks.Behavioural states modelled along the six surface location-only tracks were then tested against observed behavioural events to evaluate the model’s accuracy.Results showed that the Behavioural Change Point Analysis(BCPA)model augmented with K means clustering analysis performed well for predicting foraging behaviour(correct 86%of the time).Prediction accuracy was lower for searching(52%)and travelling(63%)behaviour,likely related to the numerical dominance of foraging events in dive data.The model’s validation for predicting foraging behaviour justified its application to nine additional surface location-only(SPOT tag)tracks,substantially increasing the utilisation of expensive and rare data.Results enabled the critical behavioural state of foraging,to be mapped throughout the entire home range of blue sharks,allowing drivers of critical habitat to be investigated.This validation strengthens the use of such modelling to interpret historic and future datasets,for blue sharks but also other species,contributing to conservational management.

Effects of distinct pollinators on the mating system and reproductive success in Incarvillea sinensis,an annual with large floral displays

Aims Most flowering plants engage in mutualisms with animals to move pollen between individuals,and it is expected that pollinators play an essential role in the evolution of selfing,yet few studies have deter-mined how distinct pollinator types affect a plant’s mating system and reproductive success differentially.We investigated the effect of two different pollinators on the reproductive success of Incarvillea sinensis,an annual with showy,insect-pollinated,one-day flowers.Methods We marked flowers after a single visit from both pollinator species(Bombus patagiatus and Amegilla quadrifasciata)and calculated the number of pollen grains deposited on the stigma and pollen left in the anthers,the fruit and seed set,the outcrossing rate and the cor-relations of paternity.Important Findings There was no significant difference in the number of pollen grains deposited on the stigma,or in the seed and fruit set between the two pollinators in both years.The mean number of pollen grains removed by B.patagiatus was significantly higher than that removed by A.quadrifasciata.The outcrossing rate of flowers pollinated by B.patagiatus was significantly higher than that of flowers pollinated by A.quadrifasciata.The correlation of paternity of flowers pollinated by B.patagiatus was significantly lower than that of flowers polli-nated by A.quadrifasciata.For I.sinensis,B.patagiatus may exhibit larger pollen wastage,thus reducing the male reproductive success of the plant,but it causes higher female reproductive success because of its higher outcrossing rate and the lower correlation of paternity.Our findings highlighted that different animal pollinators could indeed cause differential mating systems and reproductive success.

Clonal performance of Scirpus yagara in multiple levels of substrate heterogeneity and submergence

Aims Environmental heterogeneity affects the performance of clonal aquatic plants.Few researchers integrated two aspects of heterogeneity into the study of clonal plant ecology.The aims of the present study are to(i)test whether different substrate heterogeneity and submergence exert similar effects on plant performance and(ii)explore the foraging behaviour.Methods In this study,Scirpus yagara was subjected to multiple levels of substrate heterogeneity and submergence.Substrate treatments included one homogeneous substrate and three heterogeneous substrates(two-patch,four-patch and eight-patch).Water level treatments included 0,10 and 30 cm.Traits including ramet number,generation number,leaf number,bulb number,ramet height,culm length,rhizome length,clonal radius,spacer length,spacer thickness,total biomass,biomass of bulbs and biomass per bulb were measured.Important Findings Deeper water levels significantly reduced variables associated with growth such as ramet number,generation number,leaf number and bulb number,while substrate patchiness induced significant variations in traits such as spacer length and spacer thickness.Significant interactive effects of the two factors were found for ramet number,leaf number and spacer length.Scirpus yagara showed colonization towards the lake sediment patch in two-patch and four-patch substrates,and more structures were placed in the lake sediment patch.Especially for the two-patch substrate,all structures occupied the lake sediment patch.Two-sided intrusion was observed in the eight-patch substrate,which induced an even allocation of structures in different patches.The foraging behaviour was correlated with the patch size.