Adrian M. Wenner

PROMOTION OF SEED SET IN YELLOW STAR‐THISTLE BY HONEY BEES: EVIDENCE OF AN INVASIVE MUTUALISM

We examined the role of nonnative honey bees (Apis mellifera) as pollinators of the invasive, nonnative plant species yellow star-thistle (Centaurea solstitialis), both introduced to the western United States in the early to middle 1800s. Using four different treatments (three exclosure types) at flower heads, we observed visitation rates of different pollinators. Honey bees were the most common visitors at each of three transects established at three study locales in California: University of California at Davis, Cosumnes River Preserve, and Santa Cruz Island. A significant correlation existed between honey bee visitation levels monitored in all these transects and the average number of viable seeds per seed head for the same transects. Selective exclusion of honey bees at flower heads using a 3 mm diameter mesh significantly reduced seed set per seed head at all locales. Seed set depression was less dramatic at the island locale because of high visitation rates by generalist halictid bees Augochlorella ...

Honey Bee Recruitment to Food Sources: Olfaction or Language?

Honey bee recruits locate food sources by olfaction and not by use of distance and direction information contained in the recruitment dance. Recruitment efficiency increases as odor of the food source accumulates in the hive, from hour to hour and from day to day. Flight patterns, landing patterns, bee odor, and Nassanoff secretion apparently do not aid in recruitment of bees.

Geographic variation in the reproductive biology of the sand crab Emerita analoga (Stimpson) on the California coast

Reproductive characteristics were measured in 23 populations of the sand crab Emerita analoga Stimpson in midsummer over ≈ 1000 km of the California coast. Significant geographic patterns were found in the female size at maturity, the size and age distribution of ovigerous crabs, and an estimate of population fecundity. No geographic patterns were found in egg size and size-specific fecundity. Crabs from southern sites reproduced at smaller sizes and younger ages and attained smaller maximum sizes than crabs from northern sites. Young of the year crabs at northern sites matured at larger sizes, reproduced in smaller proportions, and produced larger initial clutches than southern crabs. Size at maturity and the size distribution of ovigerous crabs were inversely correlated with water temperature. Fecundity was significantly correlated with crab carapace length in all populations but no geographic trend was found in size-specific fecundity. The lack of overlap in the size ranges of ovigerous crabs did not allow direct comparisons of fecundity-size regressions between northern and southern populations. The relationships of fecundity and crab size varied significantly among populations in both the northern and the southern groups. Estimates of population fecundity decreased significantly from north to south. That trend was related to geographic patterns in the size and age distribution of ovigerous crabs.

Geographic variation in life history of the sand crab, Emerita analoga (Stimpson) on the California coast: Relationships to environmental variables

Geographic variation and the influence of environmental factors on life history characteristics of populations of a sandy intertidal decapod, Emerita analoga, Stimpson, inhabiting beaches along 8° of latitude on the California coast in midsummer were investigated for 5 yr. Female size at maturity, largest and smallest ovigerous crab size, and largest male crab size, expressed as carapace lengths, increased from south to north and were 1.5 to 3 times greater in northern than in southern populations. The observed trends in life history were associated with environmental factors that varied on regional (water temperature) and local scales (food availability and physical characteristics related to beach morphodynamics) using simple and multiple linear regression analyses. Incorporating regionally and locally varying environmental factors into a multiple linear regression model provided a better predictor of life history characteristics than any single factor. In every year, the four life history characteristics were negatively correlated with surf zone water temperature, which varied regionally and was correlated with coastline distance. Female size at maturity and the largest and smallest ovigerous crab sizes were positively correlated with food availability, estimated by chlorophyll a concentration, which was not correlated with coastline distance. Life history characteristics were not correlated with any of the beach morphodynamic variables in simple regressions. Removal of variation associated with water temperature and chlorophyll a in multiple linear regression analyses yielded positive correlations between the sizes of the largest and smallest ovigerous crabs and the size of the largest male crab, and a beach characteristic, an index of sediment size and sorting, which was not correlated with coastline distance. Female size at maturity, largest and smallest ovigerous crab sizes and largest male crab size were correlated in each year, implying that these life history traits are influenced by similar mechanisms. Little interannual variation occurred in the geographic patterns observed in life history traits. Life history traits examined in our study were correlated between years, suggesting that interactions between settlement, growth, survival, and enviroment variables were relatively consistent during our study.

Honey Bees: Do They Use the Distance Information Contained in Their Dance Maneuver?

Regular visitors at one site (experimental) in a linear series of sites normally recruit inexperienced hive mates to or near that site. If bees from a second hive were allowed to forage at both control sites, however, recruits from the experimental hive, while orienting to these sites, exhibited no evidence of having used any distance information they might have received before leaving their parent hive.

Do Honey Bees have a Language

Von Frisch and later adherents of the theory that honey bees communicate by means of an elaborate dance are challenged by controlled experiments which show that their data can be explained in terms of olfactory cues.

An Analysis of the Waggle Dance and Recruitment in Honey Bees

T E honey-bee waggle dance (Apis mellifera L.) has become one of the most extensively studied behavioral patterns among animals. During this dance within the colony certain signals apparently pass between a successful forager and a potential recruit bee. These signals contain information about direction, distance, odor, and, possibly, richness of a food source remote from the hive. Some of the evidence reported to date includes the following: (1) The direction a dancing bee heads on the vertical comb while waggling its abdomen is well correlated with the direction it has traveled on its way from the hive to the nectar source (von Frisch, 1946). (2) The length of

Simple conditioning in honey bees

Summary Large numbers of unrestrained bees have been rapidly conditioned in a laboratory situation, with later extinguishing and spontaneous recovery possible. Bees can associate either the onset of light, smoke, or, possibly, air flow with an impending reward. These results provide further evidence for plasticity of insect behaviour.

Communication with Queen Honey Bees by Substrate Sound.

A caged queen honey bee, installed in an observation hive which already contained a virgin queen, piped in response to artificial piping which was played to it through the substrate. The experiments which followed this observation provide the first direct quantitative evidence that sound, at least in the range of 600 to 2000 cycles per second, is perceived by honey bees and that information is transmitted through sound from one bee to another.

The elusive honey bee dance language hypothesis

In the mid-1930s, Karl von Frisch proposed the equivalent of an odor-search hypothesis for honey bee recruitment to food sources. A decade later he switched to the equivalent of a “dance language” hypothesis (though he apparently did not consider his conclusions as hypotheses in either case). The later and more exotic hypothesis rapidly gained acceptance, but it failed its first experimental tests in the mid-1960s; searching recruits did not behave as von Frisch indicated they should under the language hypothesis. His earlier and more conservative odor-search hypothesis meshed better with results obtained in those test experiments. Language advocates then ignored basic precepts of scientific process, rejected and/or ignored results not in accord with their favored hypothesis, and instead repeatedly sought additional supportive evidence. While so doing, they inadvertently accumulated yet more evidence counter to von Frischs original intent. By invoking ad hoc modifications and qualifications, advocates weakened, rather than strengthened, the hypothesis they continued to embrace. That strict adherence to the language hypothesis has had an unfortunate result; the exclusive investment in that line of research by various governmental agencies has failed to provide practical help to beekeepers or growers in the past half-century.