Conservation Evidence: Evidence Data

Collected Evidence: Collected Evidence: Translocate bumblebee colonies in nest boxesWe have captured three small trials in the 1950s and early 1960s testing the effect of translocating bumblebee colonies in nest boxes. Two trials in Canada provided evidence of queen death and one of these showed lower colony productivity following translocation. Just one, a UK trial, concluded that early bumblebee Bombus pratorum colonies adapt well to being moved. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F53https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F53Thu, 20 May 2010 01:34:59 +0100Collected Evidence: Collected Evidence: Reintroduce laboratory-reared bumblebee colonies to the wildSeven replicated trials have monitored the success of laboratory-reared colonies of bumblebees introduced to the environment. In four of the trials (three in the UK, one in Canada) colonies were left to develop until new queens were produced or the founding queen died. In two of these (both in the UK), the numbers of queens/colony were very low or zero. In two trials, good numbers of new queens were produced. Rates of social parasitism by cuckoo bees Bombus [Psithyrus] spp. in colonies released to the wild are variable. Two replicated trials in Canada and the UK found high rates (25-66% and 79% respectively). The UK trial showed that parasitism was reduced by placing colonies in landscapes with intermediate rather than very high nectar and pollen availability, late, rather than early in the season. Five other replicated trials reported no social parasites. We have not found evidence to compare rates of parasitism in artificial nest boxes with the rate in natural nests. Two replicated trials examined the effects of supplementary feeding for bumblebee colonies placed in the field. One, in Canada, found supplementary feeding improved the reproductive success of captive-reared colonies, but did not reduce their parasite load. The other trial, in the USA, found supplementary feeding did not increase colony productivity. One small scale trial in Norway showed that colonies of the buff-tailed bumblebee B. terrestris prefer to forage more than 100 m from their nest sites. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F52https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F52Thu, 20 May 2010 02:59:51 +0100Collected Evidence: Collected Evidence: Reintroduce laboratory-reared bumblebee queens to the wild We have found no evidence for the effects of reintroducing bumblebee queens. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F51https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F51Thu, 20 May 2010 10:18:09 +0100Collected Evidence: Collected Evidence: Translocate solitary beesOne replicated trial in India showed that translocating carpenter bees Xylocopa fenestrata in immature stages can establish a population at a new site, but if adult bees are translocated a very small proportion remain at the new site. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F55https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F55Thu, 20 May 2010 11:18:56 +0100Collected Evidence: Collected Evidence: Introduce mated females to small populations to improve genetic diversityOne trial in Brazil showed that genetic diversity can be maintained in small isolated populations of stingless bees Melipona scutellaris by regularly introducing inseminated queens. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F56https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F56Thu, 20 May 2010 15:23:26 +0100Collected Evidence: Collected Evidence: Rear and manage populations of solitary beesSeveral species of solitary bee in the family Megachilidae are reared and managed commercially as pollinators, mostly for the forage crop alfalfa, or fruit trees. These species readily nest in drilled wooden blocks, or stacked grooved boards of wood or polystyrene. Parasites and pathogens can be problematic and a number of control methods have been developed. Rearing methods have been investigated for two other species not yet commercially managed and one replicated trial shows that temperature regimes are important to survival. If rearing for conservation purposes is to be attempted, we would recommend a systematic review of these methods. Three management trials with megachilids not commercially managed in the USA or Poland, and a review of studies of managed species, found that local populations can increase up to six-fold in one year under management if conditions are good and plentiful floral resources are provided. Two replicated trials have reared solitary bees on artificial diets. One found high larval mortality in Osmia cornuta reared on artificial pollen-based diets, including honey bee-collected pollen. The other found Megachile rotundata could be reared on an artificial diet based on honey bee-collected pollen, but bees reared on synthetic pollen substitutes either died or had low pre-pupal weight. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F54https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F54Thu, 20 May 2010 18:24:45 +0100Collected Evidence: Collected Evidence: Rear declining bumblebees in captivityWe have captured 22 trials from 13 countries documenting captive rearing of bumblebee colonies by confining mated queens alone (eight trials), with one or more bumblebee workers (seven trials), honey bee workers (one trial), male bumblebee pupae (three trials) or following anaesthetisation with CO2 (four trials). One trial found that over four years of artificial rearing, Bombus terrestris queens gradually decreased in weight. Three trials have tried to rear North American bumblebees now declining or thought to be declining. Two induced spring queens of the half-black bumblebee B. vagans to rear adults in captivity, one trial induced queen yellow-banded bumblebees B. terricola (attempted in all three trials) and red-belted bumblebees B. rufocinctus (only attempted in one trial) to rear adults in captivity. All three trials tried to rear the yellow bumblebee B. fervidus and in all cases the queens laid eggs but the larvae died before becoming adults. One trial found the same pattern for the rusty-patched bumblebee and the American bumblebee B. pensylvanicus. One study reports rearing the large garden bumblebee B. ruderatus, a Biodiversity Action Plan species in the UK. Two trials have reported laboratory rearing of a pocket-making bumblebee, the Neotropical B. atratus. Three replicated trials demonstrated that the pollen diet of captively reared bumblebees influences reproductive success. In one trial, buff-tailed bumblebee B. terrestris colonies fed on freshly frozen pollen produced larger queens that survived better and produced larger colonies themselves than colonies fed on dried, frozen pollen. Two replicated trials demonstrated that B. terrestris workers can produce more offspring when fed types of pollen with a higher protein content. Two replicated experiments showed that an artificial light regime of eight hours light, 16 hours darkness, can reduce the time taken for artificially reared queen B. terrestris to lay eggs, relative to rearing in constant darkness. We have captured two replicated trials examining the effect of different artificial hibernation regimes in B. terrestris. One showed that hibernation of queens at 4-5°C for 45 days enhanced egg-laying and colony formation rates, but hibernated queens produced smaller colonies than non-hibernated queens. The second showed that queens should weigh more than 0.6 g (wet weight) and be hibernated for four months or less to have a good chance of surviving.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F50https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F50Thu, 20 May 2010 20:22:36 +0100