High juvenile annual survival probabilities in Southern Rockhopper Penguins Eudyptes chrysocome are independent of individual fledging traits

Juvenile survival is an important demographic parameter. Southern Rockhopper Penguins Eudyptes chrysocome have undergone a dramatic population decline in the past century across their distribution, but the demographic processes are poorly understood. To estimate juvenile annual survival probabilities, Rockhopper Penguin chicks from two cohorts on New Island, Falkland Islands, were marked with transponders and recorded in subsequent years using an automated gateway. We first estimated annual survival and detection probabilities using a Cormack‐Jolly‐Seber (CJS) model, and found that both probabilities were extremely high (81% in the first and 98% in the second, third and fourth years of life), even in comparison with adult birds. Because detection probability after 3 years was effectively 1, and our sample size (n = 114) was too small to explore the effects of individual traits on survival in a CJS model, we assessed whether sex, cohort, body mass and laying sequence affected whether juveniles returned to the colony during their first 3 years of life using a simple generalized linear model that assumed perfect detection. Juveniles from the first cohort and males showed a higher return probability than juveniles from the second cohort and females. There was no clear effect of fledging body mass on return rate, probably related to the favourable environmental conditions during the study period. The laying sequence did not markedly affect the return probability of chicks, indicating that, once fledged, first‐laid A‐chicks have the same probability to return as second‐laid B‐chicks despite a much larger initial maternal investment in B‐eggs in this species. This study demonstrates extraordinarily high juvenile survival probabilities and will help to understand the recent changes in the population dynamics of the Falkland Islands Southern Rockhopper Penguins.     

Temperature effects on fish production across a natural thermal gradient

Global warming is widely predicted to reduce the biomass production of top predators, or even result in species loss. Several exceptions to this expectation have been identified, however, and it is vital that we understand the underlying mechanisms if we are to improve our ability to predict future trends. Here, we used a natural warming experiment in Iceland and quantitative theoretical predictions to investigate the success of brown trout as top predators across a stream temperature gradient (4–25 °C). Brown trout are at the northern limit of their geographic distribution in this system, with ambient stream temperatures below their optimum for maximal growth, and above it in the warmest streams. A five‐month mark‐recapture study revealed that population abundance, biomass, growth rate, and production of trout all increased with stream temperature. We identified two mechanisms that contributed to these responses: (1) trout became more selective in their diet as stream temperature increased, feeding higher in the food web and increasing in trophic position; and (2) trophic transfer through the food web was more efficient in the warmer streams. We found little evidence to support a third potential mechanism: that external subsidies would play a more important role in the diet of trout with increasing stream temperature. Resource availability was also amplified through the trophic levels with warming, as predicted by metabolic theory in nutrient‐replete systems. These results highlight circumstances in which top predators can thrive in warmer environments and contribute to our knowledge of warming impacts on natural communities and ecosystem functioning.     

Pleistocene persistence and expansion in tarantulas on the Colorado Plateau and the effects of missing data on phylogeographical inferences from RADseq

Montane species endemic to the “sky islands” of the North American southwest were significantly impacted by changing climates during the Pleistocene. We combined mitochondrial and genomic data with species distribution modelling to determine whether Aphonopelma marxi, a large tarantula from the nearby Colorado Plateau, was similarly impacted by glacial climates. Genetic analyses revealed that the species comprises three main clades that diverged in the Pleistocene. A clade distributed along the Mogollon Rim appears to have persisted in place during glacial conditions, whereas the other two clades probably colonized central and northeastern portions of the species' range from refugia in canyons. Climate models support this hypothesis for the Mogollon Rim, but late glacial climate data appear too coarse to detect suitable areas in canyons. Locations of canyon refugia could not be inferred from genomic analyses due to missing data, encouraging us to explore the effect of missing loci in phylogeographical inferences using RADseq. Results from analyses with varying amounts of missing data suggest that samples with large amounts of missing data can still improve inferences, and the specific loci that are missing matters more than the number of missing loci. This study highlights the profound impact of Pleistocene climates on tarantulas endemic to the Colorado Plateau, as well as the mixed nature of the region's fauna. Some animals recently colonized from nearby deserts as glacial climates receded, whereas others, like tarantulas, appear to have persisted on the Mogollon Rim and in refugia associated with the region's famous river‐cut canyons.     

Alaskan brown bears (Ursus arctos) aggregate and display fidelity to foraging neighborhoods while preying on Pacific salmon along small streams

The interaction between brown bears (Ursus arctos) and Pacific salmon (Oncorhynchus spp.) is important to the population dynamics of both species and a celebrated example of consumer‐mediated nutrient transport. Yet, much of the site‐specific information we have about the bears in this relationship comes from observations at a few highly visible but unrepresentative locations and a small number of radio‐telemetry studies. Consequently, our understanding of brown bear abundance and behavior at more cryptic locations where they commonly feed on salmon, including small spawning streams, remains limited. We employed a noninvasive genetic approach (barbed wire hair snares) over four summers (2012–2015) to document patterns of brown bear abundance and movement among six spawning streams for sockeye salmon, O. nerka, in southwestern Alaska. The streams were grouped into two trios on opposite sides of Lake Aleknagik. Thus, we predicted that most bears would forage within only one trio during the spawning season because of the energetic costs associated with swimming between them or traveling around the lake and show fidelity to particular trios across years because of the benefits of familiarity with local salmon dynamics and stream characteristics. Huggins closed‐capture models based on encounter histories from genotyped hair samples revealed that as many as 41 individuals visited single streams during the annual 6‐week sampling season. Bears also moved freely among trios of streams but rarely moved between these putative foraging neighborhoods, either during or between years. By implication, even small salmon spawning streams can serve as important resources for brown bears, and consistent use of stream neighborhoods by certain bears may play an important role in spatially structuring coastal bear populations. Our findings also underscore the efficacy of noninvasive hair snagging and genetic analysis for examining bear abundance and movements at relatively fine spatial and temporal scales.     

No effect of blood sampling or phytohaemagglutinin injection on postfledging survival in a wild songbird

The injection of phytohaemagglutinin (PHA) and sampling of blood are widely used in studies of wild vertebrates to assess components of immune and endocrine function and health state and to obtain genetic material. Despite the pervasive use of these techniques in the life sciences, their potential effects on survival are rarely considered. For example, whether injection of the immunogen PHA into body parts critical for locomotion (e.g., the prepatagium, or wing web, in birds) affects survival has not been tested. Here, we test whether injection of PHA into the wing web and blood sampling from nestling house wrens affects their subsequent recruitment and survival as breeding adults. Capture‐mark‐recapture analysis on a large sample of young (N = 20,152 fledglings from 3959 broods) treated over 10 years revealed that neither PHA injection nor blood sampling affected individual survival and detection probability. Recruitment as a breeder varied among years, but this variation was not attributable to sampling effort, or the percent of all adults identified at the nest during a given year. Variation in the percent of adults identified was primarily attributable to the effect of nest depredation on our ability to capture nesting pairs. Our results indicating lack of an effect of blood sampling and immune stimulation on survival are encouraging, but we recommend further work to assess the potential negative effects of all commonly used techniques on the survival of study subjects in the wild, including the potential costs associated with mounting various immunological responses.     

Assessing the abundance of Bristol Bay belugas with genetic mark‐recapture methods

The Bristol Bay stock of beluga whales (Delphinapterus leucas) is genetically distinct and resides in Bristol Bay year‐round. We estimated the abundance of this population using genetic mark‐recapture, whereby genetic markers from skin biopsies, collected between 2002 and 2011, were used to identify individuals. We identified 516 individual belugas in two inner bays, 468 from Kvichak Bay and 48 from Nushagak Bay, and recaptured 75 belugas in separate years. Using a POPAN Jolly‐Seber model, abundance was estimated at 1,928 belugas (95% CI = 1,611–2,337), not including calves, which were not sampled. Most belugas were sampled in Kvichak Bay at a time when belugas are also known to occur in Nushagak Bay. The pattern of genetic recaptures and data from belugas with satellite transmitters suggested that belugas in the two bays regularly mix. Hence, the estimate of abundance likely applies to all belugas within Bristol Bay. Simulations suggested that POPAN estimates of abundance are robust to most forms of emigration, but that emigration causes negative bias in both capture and survival probabilities. Because it is likely that some belugas do not enter the sampling area during sampling, our estimate of abundance is best considered a minimum population size.     

Site fidelity of intertidal fish to rockpools

Gobius paganellus, Lipophrys pholis and Coryphoblennius galerita are wide‐spread intertidal fish that spend their earlier life stages in rock pools, and yet very little is known about their site fidelity behaviour. For these species, fidelity to rockpools may result in increased fitness costs in a predicted scenario of warmer sea water, due to the low thermal inertia of these water bodies. In this context, it is relevant to investigate these species' site fidelity. We made a mark‐recapture study to assess the mentioned species' movements within and between rockpools. We tagged a total of 530 individuals of the aforementioned species with the Visible Implant Elastomer and tracked their movement for a 7‐month period. We found that site fidelity and specific rockpools conditions are important factors in distribution of intertidal blennies and gobies. We also examined the relations between rockpool volume, depth and site fidelity. We found that G. paganellus tends to remain in its original marking pool, with an average recapture rate of 20.5%, but showed no evidence of inter‐pool movement. Rockpool depth, however, proved to be important in the blennies' movements. Our findings are among the first to prove that a mark‐recapture method can be successfully used to track intertidal fish movements. In particular, we showed that G. paganellus presents site fidelity in intertidal rockpools during its early ontogeny for a period of two to three months.     

Behaviour of sexually deceived ichneumonid wasps and its implications for pollination in Cryptostylis (Orchidaceae)

Pollination via sexual deception is hypothesised to be associated with more frequent outcrossing and greater pollen dispersal distances than strategies involving food‐foraging behaviour. In this study, we investigated the behaviour and movement distances of Lissopimpla excelsa (Hymenoptera: Ichneumonidae), and their implications for the pollination of the sexually deceptive Cryptostylis ovata (Orchidaceae). Pollinator observations revealed that while L. excelsa will alight on multiple flowers within a single visit to a patch of orchids, the frequency of attempted copulation decreases with successive visits, suggesting that pollinator learning may inhibit within‐patch pollen transfer. Mark‐recapture demonstrated that 25% of wasps revisited inflorescences within a day and 50% revisited within a week. Despite the apparent site fidelity of some individuals, L. excelsa often move over large distances (maximum = 625 m), and are capable of dispersing pollen between patches. To resolve the consequences of pollination by sexual deception of ichneumonids, we compared our results with those from studies of other sexually deceptive systems. While pollination rates were comparable with other sexually deceptive orchids, L. excelsa showed high rates of column contact and moved over large distances relative to other sexually deceived pollinators. Among sexually deceptive orchids in general, the frequency of column contact was not correlated either with the frequency of pseudocopulation or with pollination rate. These results suggest that the consequences of pollination by sexual deception may vary extensively between plant taxa due to variation in floral traits, and behavioural differences between pollinator groups.     

Consumptive and non‐consumptive effects of wolf spiders on cotton bollworms

Larvae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) that survive on genetically modified Bt cotton (Gossypium hirsutum L., Malvaceae) contribute to the risk of widespread resistance to Bt toxins. Current resistance management techniques include pupae busting, which involves deep tilling of the soil to kill overwintering pupae. Unfortunately, pupae busting runs counter to soil and water conserving techniques, such as minimum tillage. This problem could be relieved with biological control methods, whereby predators attack either larvae going to ground to pupate or moths emerging from the ground. We found that the wolf spider Tasmanicosa leuckartii (Thorell) (Araneae: Lycosidae), a common inhabitant of Australian cotton agroecosystems, is an effective predator of H. armigera, attacking and killing most larvae (66%) and emerging moths (77%) in simple laboratory arenas. Tasmanicosa leuckartii also reduced the number of emerging moths by 66% on average in more structurally complex glasshouse arenas. Males, females, and late‐instar juveniles of T. leuckartii were similarly effective. Tasmanicosa leuckartii also imposed non‐consumptive effects on H. armigera, as when a spider was present larvae in the laboratory areas spent less time on the cotton boll and more time on the soil and more mass was lost from the cotton boll. Increased loss of boll mass likely reflects changes in H. armigera foraging behavior induced by the presence of spiders (indirect non‐consumptive effects). Helicoverpa armigera spent more time as pupae when the spider was present in simple laboratory arenas, but not in more complex glasshouse enclosures. Overall, results indicate that T. leuckartii spiders can be effective predators of H. armigera late instars and moths but also suggest that, under some conditions, the presence of spiders could increase the damage to individual cotton bolls.     

Decline in local abundance of bottlenose dolphins (Tursiops truncatus) in the Bay of Islands,New Zealand

Regional populations of bottlenose dolphins (Tursiops truncatus) around New Zealand are genetically isolated from each other and the species was recently classified as nationally endangered based on relatively small population sizes and reports of high calf mortality. Here, we estimate the abundance and trends in one of these regional populations, the Bay of Islands, using a photo‐identification database collected from 1997 to 1999 and from 2003 to 2006, containing a total of 3,841 records of 317 individual dolphins. Estimates of abundance obtained with the robust design fluctuated widely but showed a significant decline in the number of dolphins present in the bay over time (7.5% annual rate of decline). Temporary emigration was random and fluctuated considerably (γ  =  0.18, SE = 0.07 to γ  =  0.84, SE = 0.06). Apparent survival was estimated at 0.928 (CI = 0.911–0.942). Seasonal estimates (26 seasons) obtained in POPAN also showed a significant decline in abundance (5.8% annual rate of decline). Despite the decline observed in local abundance, dolphins continue to be found regularly in the Bay of Islands, suggesting that fewer dolphins use the bay on regular basis. Consequently, it seems that a change in habitat use, mortality and possibly low recruitment could underlie the apparent local decline.     

Effect of diet on survival,in the laboratory and the field,of sterile male Mediterranean fruit flies

To improve the effectiveness of the sterile insect technique against the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), our objectives in this study were two‐fold. First, to evaluate the ability of sterile males of the Vienna‐8 strain to survive starvation, we compared them to wild males under laboratory conditions. The second objective was to determine the effect of protein‐rich nutrition on sterile male fly survival, under starvation conditions in the laboratory, under semi‐natural conditions in a field enclosure, and under natural conditions in the open field. Therefore, we released marked sterile flies of the two diet regimes, protein‐fed or protein‐deprived, and monitored their survival by recapturing them after 4, 6, and 7 days. In the laboratory, wild males endured starvation significantly better than sterile ones and protein addition to sterile fly diet resulted in even greater reduced capability to endure starvation. On the other hand, the addition of protein to sterile‐male diet did not affect their ability to survive in a field enclosure or in the open field. We conclude that under natural conditions, where food is available, sterile male fly survival is unaffected by protein‐rich pre‐release diet.     

Survival and abundance of short‐finned pilot whales in the archipelago of Madeira,NE Atlantic

Estimates of population parameters for the short‐finned pilot whale, Globicephala macrorhynchus, are scarce in literature, contributing to an International Union for Conservation of Nature (IUCN) status of Data Deficient. In this study, photo‐identification data collected over 7 yr from Madeira were used to estimate for the first time survivorship, capture probability, and abundance in this species using mark‐recapture methodology. The Cormack‐Jolly‐Seber model estimated that the adult island‐associated (i.e., resident and regular visitor) whales had a constant survival rate of 0.960 (95% CI: 0.853–0.990) and an annual capture probability varying between 0.372 (CI: 0.178–0.619) and 0.843 (CI: 0.619–0.947). A parameterization of the Jolly‐Seber model estimated that 140 island‐associated whales (CI: 131–151) used the area throughout the course of the study. Based on a closed population model, the most precise (lower CV) annual estimate of the total number of pilot whales using the southern and eastern waters of Madeira (~900 km²) in a 3 mo period covering summer/autumn was 334 animals (CI: 260–437). No trend was observed. Despite including biases, the approach used in this study provided plausible estimates of population parameters, which can contribute to the regional conservation strategies.     

Three physical barriers with obvious effects on Carposina sasakii selection behavior to two dominant jujube tree volatiles

The peach fruit moth (PFM), Carposina sasakii Matsumura (Lepidoptera: Carposinidae), a severe pest of Ziziphus jujuba Miller fruit trees (jujube, Rhamnaceae) mainly grown in China, has increasingly hindered the development of the jujube industry in recent years. In order to provide a theoretical basis for a physical obstruction method, we evaluated the effect of three commonly sold physical barriers on PFM host‐searching behavior. Two principal volatiles generated by the jujube tree, α‐farnesene and cis‐3‐hexenyl acetate (leaf acetate), were used as references to detect electroantennography (EAG) response values of 2‐, 4‐, and 6‐day‐old PFM adults. The results indicated different EAG responses toward α‐farnesene and leaf acetate between different ages of PFM, and males responded differently than females. The EAG responses were stronger in 4‐day‐old males to leaf acetate and in 2‐day‐old females to α‐farnesene. The two‐choice behavioral Y‐tube olfactometer assay confirmed that PFM was strongly attracted to α‐farnesene and leaf acetate. We determined the EAG and behavioral responses of PFM after spraying three kinds of physical barriers: Liquid Film Fruit Bag, High Lipid Film, and Jujube Protection No. 1. We obtained strong inhibitory effects on PFM attraction to both volatile lures using these barriers, including negative taxis by both females and males to Liquid Film Fruit Bag and Jujube Protection No. 1. We can infer that Liquid Film Fruit Bag is the most promising potential physical barrier for PFM control, with Jujube Protection No. 1 ranking as second‐best.     

Combining hyperspectral imaging and chemometrics to assess and interpret the effects of environmental stressors on zebrafish eye images at tissue level

Changes on an organism by the exposure to environmental stressors may be characterized by hyperspectral images (HSI), which preserve the morphology of biological samples, and suitable chemometric tools. The approach proposed allows assessing and interpreting the effect of contaminant exposure on heterogeneous biological samples monitored by HSI at specific tissue levels. In this work, the model example used consists of the study of the effect of the exposure of chlorpyrifos‐oxon on zebrafish tissues. To assess this effect, unmixing of the biological sample images followed by tissue‐specific classification models based on the unmixed spectral signatures is proposed. Unmixing and classification are performed by multivariate curve resolution‐alternating least squares (MCR‐ALS) and partial least squares‐discriminant analysis (PLS‐DA), respectively. Crucial aspects of the approach are: (1) the simultaneous MCR‐ALS analysis of all images from 1 population to take into account biological variability and provide reliable tissue spectral signatures, and (2) the use of resolved spectral signatures from control and exposed populations obtained from resampling of pixel subsets analyzed by MCR‐ALS multiset analysis as information for the tissue‐specific PLS‐DA classification models. Classification results diagnose the presence of a significant effect and identify the spectral regions at a tissue level responsible for the biological change.