Janis L. Dickinson

Citizen Science: A Developing Tool for Expanding Science Knowledge and Scientific Literacy

Citizen science enlists the public in collecting large quantities of data across an array of habitats and locations over long spans of time. Citizen science projects have been remarkably successful in advancing scientific knowledge, and contributions from citizen scientists now provide a vast quantity of data about species occurrence and distribution around the world. Most citizen science projects also strive to help participants learn about the organisms they are observing and to experience the process by which scientific investigations are conducted. Developing and implementing public data-collection projects that yield both scientific and educational outcomes requires significant effort. This article describes the model for building and operating citizen science projects that has evolved at the Cornell Lab of Ornithology over the past two decades. We hope that our model will inform the fields of biodiversity monitoring, biological research, and science education while providing a window into the culture of citizen science.

Ecology and evolution of cooperative breeding in birds

Introduction Walter D. Koenig and Janis L. Dickinson 1. Evolutionary origins J. David Ligon and D. Brent Burt 2. Delayed dispersal Jan Ekman, Janis L. Dickinson, Ben J. Hatchwell and Michael Griesser 3. Fitness consequences of helping Janis L. Dickinson and Ben J. Hatchwell 4. Parental care, load-lightening and costs Robert G. Heinsohn 5. Matings systems and sexual conflict Andrew Cockburn 6. Sex-ratio manipulation Jan Komdeur 7. Physiological ecology Morne Du Plessis 8. Endocrinology Steven J. Schoech, S. James Reynolds and Raoul K. Boughton 9. Incest and incest avoidance Walter D. Koenig and Joseph Haydock 10. Reproductive skew Robert D. Magrath, Rufus A. Johnstone and Robert G. Heinsohn 11. Joint-laying systems Sandra L. Vehrencamp and James S. Quinn 12. Conservation biology Jeffrey R. Walters, Caren B. Cooper, Susan J. Daniels, Gilberto Pasinelli and Karen Schiegg 13. Mammalian contrasts and comparisons Andrew F. Russell Summary Steven J. Pruett-Jones Names of bird and mammal species mentioned in the text References Index.

The current state of citizen science as a tool for ecological research and public engagement

Approaches to citizen science – an indispensable means of combining ecological research with environmental education and natural history observation – range from community-based monitoring to the use of the internet to “crowd-source” various scientific tasks, from data collection to discovery. With new tools and mechanisms for engaging learners, citizen science pushes the envelope of what ecologists can achieve, both in expanding the potential for spatial ecology research and in supplementing existing, but localized, research programs. The primary impacts of citizen science are seen in biological studies of global climate change, including analyses of phenology, landscape ecology, and macro-ecology, as well as in sub-disciplines focused on species (rare and invasive), disease, populations, communities, and ecosystems. Citizen science and the resulting ecological data can be viewed as a public good that is generated through increasingly collaborative tools and resources, while supporting public participation in science and Earth stewardship.

Eunuchs: The Role of Apyrene Sperm in Lepidoptera?

Moths and butterflies (Lepidoptera) generally produce two types of spermatozoa: a typical nucleated (eupyrene) spermatozoon and a smaller anucleate (apyrene) spermatozoon. The apyrene sperm often predominate over the eupyrene sperm in an ejaculate and, in the female, they migrate actively to the sperm storage organ, the spermatheca. There they usually degenerate, apparently not playing any role in fertilization of the eggs. Several hypotheses for the function of the apyrene sperm have been proposed. These center around the notions that the apyrene sperm may assist the eupyrene sperm in their migration from the testes in the male to the spermatheca in the female or that they function as a nutritional supplement in the female. No experimental support for these notions has been adduced and observational evidence seems to argue against them. We propose that apyrene sperm may play, at least additionally, a role in competition between rival sperm deposited by different males. They may either eliminate, by displacement or inactivation, eupyrene sperm from previous matings or prevent or delay further mating by the female. Several peculiar attributes of the apyrene sperm support these hypotheses. Their much simplified morphology and frequent large preponderance over the eupyrene sperm, their immediate activation during ejaculation and consequent rapid migration to the spermatheca, suggest they might act to overwhelm any sperm stored there from previous matings. The same attributes would also serve to stuff the spermatheca as efficiently and completely as possible, thus perhaps signaling a successful insemination to the female and thereby reducing her receptivity to further mating. We suggest that apyrene sperm are a morphological manifestation of a more widespread phenomenon wherein accessory sperm may play an important role in sperm competition.

Prolonged mating in the milkweed leaf beetle Labidomera clivicollis clivicollis (Coleoptera: Chrysomelidae): a test of the “sperm-loading” hypothesis

SummaryFemale milkweed leaf beetles (Labidomera clivicollis clivicollis) frequently mate with more than one male, and pairs form mating associations which last for up to 42 h in the field. I tested the hypothesis that males remaining with females for long periods of time benefit by numerically overwhelming the sperm of their competitors. Male L.c.clivicollis copulated intermittently with females throughout an 11 hour period in the laboratory. When virgin females were allowed a single copulation, 94.3% of the sperm they received were located in the spermatheca immediately afterward. Males were not sperm-depleted, for they had large numbers of sperm available after one copulation (mean=230,000±43,200); the maximal number of sperm a male transferred to a female in 24 h was 30,500. There was a positive linear relationship between the number of sperm transferred and time up to 24 h after mounting (r2=0.178, P<0.003). These data suggest that males transfer increasing numbers of sperm throughout a 24-h-period. Mating duration was the most important determinant of paternity when females were placed with one male for 24 h and another male for 6 hours. Females whose first matings were longer showed first male sperm predominance (as determined by starch-gel electrophoresis), while females whose second matings were longer showed last male sperm predominance. In view of these data, it is puzzling that males do not inseminate with large numbers of sperm immediately after mounting the female. It is possible that female refractory behaviors make insemination difficult and favor prolonged mating by male milkweed leaf beetles.

Life-history variation predicts the effects of demographic stochasticity on avian population dynamics

Comparative analyses of avian population fluctuations have shown large interspecific differences in population variability that have been difficult to relate to variation in general ecological characteristics. Here we show that interspecific variation in demographic stochasticity, caused by random variation among individuals in their fitness contributions, can be predicted from a knowledge of the species’ position along a “slow‐fast” gradient of life‐history variation, ranging from high reproductive species with short life expectancy at one end to species that often produce a single offspring but survive well at the other end of the continuum. The demographic stochasticity decreased with adult survival rate, age at maturity, and generation time or the position of the species toward the slow end of the slow‐fast life‐history gradient. This relationship between life‐history characteristics and demographic stochasticity was related to interspecific differences in the variation among females in recruitment as well as to differences in the individual variation in survival. Because reproductive decisions in birds are often subject to strong natural selection, our results provide strong evidence for adaptive modifications of reproductive investment through life‐history evolution of the influence of stochastic variation on avian population dynamics.

Citizen science: a new approach to advance ecology, education, and conservation

Citizen science has a long history in the ecological sciences and has made substantial contributions to science, education, and society. Developments in information technology during the last few decades have created new opportunities for citizen science to engage ever larger audiences of volunteers to help address some of ecology’s most pressing issues, such as global environmental change. Using online tools, volunteers can find projects that match their interests and learn the skills and protocols required to develop questions, collect data, submit data, and help process and analyze data online. Citizen science has become increasingly important for its ability to engage large numbers of volunteers to generate observations at scales or resolutions unattainable by individual researchers. As a coupled natural and human approach, citizen science can also help researchers access local knowledge and implement conservation projects that might be impossible otherwise. In Japan, however, the value of citizen science to science and society is still underappreciated. Here we present case studies of citizen science in Japan, the United States, and the United Kingdom, and describe how citizen science is used to tackle key questions in ecology and conservation, including spatial and macro-ecology, management of threatened and invasive species, and monitoring of biodiversity. We also discuss the importance of data quality, volunteer recruitment, program evaluation, and the integration of science and human systems in citizen science projects. Finally, we outline some of the primary challenges facing citizen science and its future.

Family-based winter territoriality in western bluebirds, Sialia mexicana: the structure and dynamics of winter groups

Winter residency is characteristic of the majority of cooperatively breeding birds, but the composition and dynamics of winter groups have been examined in relatively few. In 1996-1998, we examined winter territoriality in the western bluebird, a year-round resident that shows a limited degree of helping behaviour in central coastal California, U.S.A. In spring, most western bluebirds breed as socially monogamous pairs, but a small proportion of pairs (3-16%) have additional breeding-age males helping at the nest, usually assisting parents or brothers. We found that year-round residents commonly wintered in family groups that defended territories similar to those used in spring. Winter groups had an even sex ratio and formed early in the autumn, when hatch-year birds dispersed. More females than males left their natal groups to be replaced by an influx of immigrant hatch-year birds. Winter groups typically consisted of breeders and one or two sons from the prior breeding season along with one or more immigrant females. A second period of dispersal occurred in spring when winter groups broke up and most birds other than the breeding pair left the winter territory. When they bred, yearling males and females often bred with unrelated individuals from their winter groups. Sons were more likely to remain on the study area as yearlings when they wintered with both parents than when they wintered with just one parent. We suggest that young males stay the winter due to benefits of remaining in family groups on mistletoe-based winter territories. Subsequent localized dispersal of sons then leads to opportunistic kin-based interactions later in life. Copyright 2001 The Association for the Study of Animal Behaviour.

Extrapair paternity, inclusive fitness, and within-group benefits of helping in western bluebirds

In central coastal California, USA, 3–16% of western bluebird (Sialia mexicana) pairs have adult male helpers at the nest. Demographic data on a colour‐ringed population over a 13‐year period indicate that helpers gain a small indirect fitness benefit through increases in the number of young fledged from nests of close kin. A small proportion of adult helpers (16%) that were able to breed and help simultaneously had higher annual inclusive fitness than males that only bred. These males comprised such a minor proportion of helpers that the mean fitness of helpers was still lower than the mean fitness of independent breeders. We used DNA fingerprinting to determine whether extrapair fertilizations alter within‐group benefits enough to tip the balance in favour of helping behaviour. Overall, 19% of 207 offspring were sired by males other than their social father and extrapair fertilizations occurred in 45% of 51 nests. Intraspecific brood parasitism was rare so that mean mother‐nestling relatedness approximated the expected value of 0.5. Extrapair paternity reduced putative father‐offspring relatedness to 0.38. Mean helper‐nestling relatedness was 0.41 for helpers assisting one or both parents and 0.28 for helpers aiding their brothers. Helpers rarely sired offspring in the nests at which they helped. Helping was not conditional on paternity and helpers were not significantly more closely related to offspring in their parents’ nests than to offspring in their own nests. Although helpers may derive extracurricular benefits if helping increases their own or their fathers opportunities for extrapair fertilizations, within‐nest inclusive fitness benefits of helping do not compensate males for failing to breed. Breeding failure and constraints on breeding are the most likely explanations for why most helpers help.

Extrapair copulations in western bluebirds (Sialia mexicana): female receptivity favors older males

Abstract. Extrapair paternity has been the focus of numerous studies of socially monogamous birds, but the dynamics of extrapair male-female interactions have been explored in relatively few. In western bluebirds (Sialia mexicana), a species with 20% extrapair paternity, two to four observers monitored extrapair copulations (EPCs) occurring on the females home territory while her social mate was detained in a cage near the nest. Detention elevated the frequency and visibility of EPCs, so we could score receptivity of females to identifiable extrapair males without the interference of intermale aggression. Most intruding extrapair males were neighboring breeders visiting outside their own mates fertile period. Local male relatives of the detained male attempted nonincestuous EPCs, but neighboring sons did not attempt to copulate with their mothers and, in some cases, chased away intruders. Female receptivity was not influenced by whether the detained mate was visually present or hidden behind cloth and did not increase with the persistence or relative size of the extrapair male. Female receptivity increased with the age difference between the extrapair male and the females social mate, suggesting that females prefer older males as extrapair partners. This study suggests that costs of resistance are relatively unimportant in determining female receptivity in western bluebirds, but identifies preferential receptivity to older males as a potential factor in the outcome of inter- and intrasexual conflict over paternity.