Impact of chronic neonicotinoid exposure on honeybee colony performance and queen supersedure

BACKGROUND: Honeybees provide economically and ecologically vital pollination services to crops and wild plants. During the last decade elevated colony losses have been documented in Europe and North America. Despite growing consensus on the involvement of multiple causal factors, the underlying interactions impacting on honeybee health and colony failure are not fully resolved. Parasites and pathogens are among the main candidates, but sublethal exposure to widespread agricultural pesticides may also affect bees. METHODOLOGY/PRINCIPAL FINDINGS: To investigate effects of sublethal dietary neonicotinoid exposure on honeybee colony performance, a fully crossed experimental design was implemented using 24 colonies, including sister-queens from two different strains, and experimental in-hive pollen feeding with or without environmentally relevant concentrations of thiamethoxam and clothianidin. Honeybee colonies chronically exposed to both neonicotinoids over two brood cycles exhibited decreased performance in the short-term resulting in declining numbers of adult bees (-28%) and brood (-13%), as well as a reduction in honey production (-29%) and pollen collections (-19%), but colonies recovered in the medium-term and overwintered successfully. However, significantly decelerated growth of neonicotinoid-exposed colonies during the following spring was associated with queen failure, revealing previously undocumented long-term impacts of neonicotinoids: queen supersedure was observed for 60% of the neonicotinoid-exposed colonies within a one year period, but not for control colonies. Linked to this, neonicotinoid exposure was significantly associated with a reduced propensity to swarm during the next spring. Both short-term and long-term effects of neonicotinoids on colony performance were significantly influenced by the honeybees' genetic background. CONCLUSIONS/SIGNIFICANCE: Sublethal neonicotinoid exposure did not provoke increased winter losses. Yet, significant detrimental short and long-term impacts on colony performance and queen fate suggest that neonicotinoids may contribute to colony weakening in a complex manner. Further, we highlight the importance of the genetic basis of neonicotinoid susceptibility in honeybees which can vary substantially.

Perspective: LaGuardia Community College Newsletter Vol. 1, No. 5

A newsletter published periodically to keep the faculty, students, staff, and community informed about the activities taking place on the campus of LaGuardia Community College. Cover article: SONY SHIFT SCHEDULED SOON, SPOKESMAN SAYS. Other entries include: CUNY TEACHING EXCELLENCE AWARD TO PROFESSOR MILLER; CHILD CARE LEAVE ADOPTED BY BHE; NINETY SENIOR CITIZENS RECEIVE CERTIFICATES; COLLEGE COMMENCEMENT TO BE HELD AT QUEENS COLLEGE AUDITORIUM; DEAN PALMER TO SING AT SEPT. 16, COMMENCEMENT; FOUR MORE PARAPROFESSIONALS COMPLETE DEGREES.”

Nesting architecture and population structure of the fungus-growing ant Cyphomyrmex transversus (Formicidae: Myrmicinae: Attini) in the Brazilian coastal zone of Ilheus, Bahia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Vitrification with DAP 213 and Cryotop of Ex Situ and In Situ Feline Cumulus-Oocyte Complexes

This study was undertaken to compare cryotolerance, in terms of viability and resumption of meiosis after warming and culture (24 and 48 h), of ex situ (isolated) and in situ (enclosed in the ovarian tissue) feline cumulusoocyte complexes (COCs) vitrified with DAP 213 (2 M DMSO, 1 M acetamide, 3 M propylene glycol) in cryotubes or Cryotop method. Ovaries were harvested from 49 pubertal queens. of each pair of ovaries, one was dissected to release COCs randomly divided into three groups: fresh COCs (control), ex situ COCs vitrified with DAP 213 and Cryotop. The cortex of the other ovary was sectioned into small fragments (approximately 1.5 mm3) and randomly assigned to be vitrified by DAP 213 or Cryotop. After warming, ex situ and in situ (retrieved form vitrified ovarian tissue) COCs were matured in vitro. Viability of oocytes was highly preserved after warming and culture in all treatments. Proportions of oocytes surrounded by complete layers of viable cumulus cells were remarkably decreased (p < 0.00001) in both vitrification procedures compared to fresh oocytes. Resumption of meiosis occurred in all treatments. After 24 h of culture, results were similar in ex situ and in situ vitrified oocytes regardless of the vitrification protocol used (range 29-40%), albeit lower (p < 0.05) than those of fresh oocytes (65.8%). After 48 h of culture, ex situ oocytes vitrified with Cryotop achieved the rates of meiosis resumption similar to fresh oocytes (53.8% vs 67.5%; p > 0.05) and ex situ and in situ oocytes vitrified with DAP 213 showed similar rates of resumption of meiosis. These findings demonstrated that DAP 213 and Cryotop preserve the viability of ex situ and in situ oocytes, but cumulus cells are highly susceptible to vitrification. However, the capability to resume meiosis evidences that feline immature oocytes vitrified as isolated or enclosed in the ovarian cortex have comparable cryotolerance.

Chemical Composition of Lipids Present in Cat and Dog Oocyte by Matrix-Assisted Desorption Ionization Mass Spectrometry (MALDI- MS)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ovarian remnant syndrome in small animals

The ovarian remnant syndrome (ORS) is an iatrogenic disorder in bitches and queens, which is characterized by recurrence of estrus following surgical spay, due to the presence of a piece of ovarian tissue within the abdominal cavity. In most cases, the remnant ovary is found in the right ovarian pedicle, due to its topographic position, deeper and more cranial than the left ovary. The main clinical signs of ORS in small animals are the heat behavior and the presence of vaginal swelling/secretion, especially in canines. The diagnosis should be performed by means of vaginal cytology when attraction of males is detected, serum estrogen and progesterone levels and/or by challenging test with GnRH or hCG administration. However, vaginal citology is the most suitable and less expensive diagnostic tool. Nowadays the treatment of choice is a new laparotomy or laparoscopy, followed by removal of the remnant ovarian tissue. The surgical treatment has more chances of success if it is performed in the diestrus (i.e., between 15 and 60 days after the detection of attraction of males). Furthermore, a careful and accurate surgical procedure aided by advanced visualization techniques during ovariohysterectomy or ovariectomy is the best way to prevent ORS in companion animals.

Comparison of efficiency between two artificial insemination methods using frozen-thawed semen in domestic cat (Felis catus) Artificial insemination in domestic cats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Unsuccessful attacks dominate a drone-preying wasp's hunting performance near stingless bee nests

Bee males (drones) of stingless bees tend to congregate near entrances of conspecific nests, where they wait for virgin queens that initiate their nuptial flight. We observed that the Neotropical solitary wasp Trachypus boharti (Hymenoptera, Cabronidae) specifically preys on males of the stingless bee Scaptotrigona postica (Hymenoptera, Apidae); these wasps captured up to 50 males per day near the entrance of a single hive. Over 90% of the wasp attacks were unsuccessful; such erroneous attacks often involved conspecific wasps and worker bees. After the capture of non-male prey, wasps almost immediately released these individuals unharmed and continued hunting. A simple behavioral experiment showed that at short distances wasps were not specifically attracted to S. postica males nor were they repelled by workers of the same species. Likely, short-range prey detection near the bees' nest is achieved mainly by vision whereas close-range prey recognition is based principally on chemical and/or mechanical cues. We argue that the dependence on the wasp's visual perception during attack and the crowded and dynamic hunting conditions caused wasps to make many preying attempts that failed. Two wasp-density-related factors, wasp-prey distance and wasp-wasp encounters, may account for the fact that the highest male capture and unsuccessful wasp bee encounter rates occurred at intermediate wasp numbers.

Ultramorphology of the Digestive Tract of Paratrechina longicornis (Hymenoptera, Formicidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Changes in the morphology and ultrastructure of the Dufour's gland during the life cycle of the bumble bee queen, Bombus terrestris L-(Hymenoptera : Bombini)

The Dufour's gland is found closely associated with the sting apparatus of all female hymenopterans, playing multiple roles among bees. In some species of Bombus the gland may be involved in production of nestmate recognition pheromones, but in B. terrestris its function is not certain yet. The morphology of the :Dufour's gland of B. terrestris queens and the ultrastructural features of its cells were studied in different ages and behavioural stages using routine transmission electron microscopy. Measurements of the length and the diameter of the gland in the same conditions were also made. The Dufour's gland of the queen increases significantly in size (both in length and in diameter) with age and reproductive activity the ultrastructural features of the gland show electrondense material that comes from the haemolymph. This material is also present in the intercellular spaces, and is conducted to the subcuticular space, to be released directly into the glandular lumen. Hence at least part of the secretion is probably taken up directly from the haemolymph. The ultrastructural features indicate a more active phase of the gland corresponding to the period of egg-laying of the queen, and a decrease in activity when the queen is in hibernation as well as after the competition point. In conclusion, the gland is probably involved in reproduction, more specifically, in the marking off eggs.

Electrophoretical polypeptide pattern of hypopharyngeal glands extracts from workers and males of Scaptotrigona postica Latr. (Hymenoptera, Apidae, Meliponinae)

In S. postica the hypopharyngeal glands are present in workers, males and queens. The glands of newly emerged workers are in a prefunctional phase, in nurse workers they reach their highest development and in forager workers they suffer reabsorption. The newly emerged males and queens, however, have well developed glands that soon start involution. The electrophoretical pattern of worker and male hypopharyngeal glands is compared with the pattern of nurse workers of A. mellifera. The results show simularities, as well as differences among the S. postica males and workers, and among the phases of worker life. The electrophoretic band pattern suggests that the hypopharyngeal glands of nurse workers of S. postica produce substances similar to the ones produced by A. mellifera. The similarity of the extracts of nurse glands of A. mellifera and S. postica, as well as the behavioural similarities of the workers, suggest the same function of this gland in both species.

Class III glands in the abdomen of Meliponini

Class III tegumentar glands were studied in workers, as well as in queens and males when available, of 56 Meliponini species. The presence and development of these glands varies widely among and within species. However, the queen typically has more glands than do workers, and males rarely have any. Gland development in workers was evaluated by counting and determining the size of cells in histological sections. Laying queens were found to have more active gland cells than did virgins. Cell numbers and cell ultrastructure differed among glands similarly located in workers, queens and males. Cell size and ultrastructure also varied from tergite to tergite. In conclusion, since it is likely that most of them produce pheromones, the wide variability in these glands suggests that they are important to social interaction.

Alterations induced by the juvenile hormone in glandular cells of the Apis mellifera venom gland: Applications on newly emerged workers (Hymenoptera, Apidae)

Histological and histochemical analyses were carried out in order to evaluate the influence of the topical application of a synthetic juvenile hormone on the secretory cycle and degeneration of the venom gland of Apis mellifera. Newly emerged workers received the topical application of synthetic hormone and the results were compared to the normal development of the secretory cycle in virgin and mated queens. The first worker group received the juvenile hormone diluted in hexane (2 mu g/mu L), the second received only mu L of hexane, and the third did not receive any kind of application. After the application the workers were returned to the colony and collected at the ages of 14 and 25 days of adult life. The groups with virgin queens and the other with mated queens, did not receive the treatment. The results show that the individuals treated with juvenile hormone and with pure hexane presented differences in the histological and cytochemical aspects of the secretory cells of the venom gland. The data indicate that both the juvenile hormone and hexane accelerate the activity of the secretory cycle and the degeneration of the venom gland; however, the juvenile hormone proved to be more effective than hexane. (c) 2006 Elsevier Ltd. All rights reserved.

Secretory cycle of the Dufour's gland in workers of the bumble bee Bombus terrestris L-(Hymenoptera : Apidae, Bombini)

The Dufour's gland of Bombus terrestris workers, of different ages and with varying degrees of ovary development, was studied with the aim to verify its involvement in reproduction. Measurements of the diameter and the length of the gland were made using an ocular micrometer adapted to a microscope. Transmission electron microscopy was used to study the morphology of the secretory cells and to analyze the secretory cycle. The glandular cells were considered to be near type II cells of NOIROT and QUENNEDEY (1974), a type that has not been described before in Hymenopterans. The results show that there is a correlation between the degree of ovary development and Dufour's gland activity of workers. The diameter of the gland and the secretory cell activity increased with increasing oocyte size in the ovary. Regressive conditions of the gland were observed, which are probably related to increasing worker age. To elucidate the production and releasing process of the secretion and to establish its precise function, a comparative analysis of the secretion process of the Dufour's gland of queens and workers is needed.

Cephalic salivary glands of two species of advanced eusocial bees (Hymenoptera: Apidae): morphology and secretion

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)