Laying sequence, diploid males, and nest usurpation in the leafcutter bee,Megachile rotundata (Hymenoptera: Megachilidae)

1994 ◽  
Vol 7 (5) ◽  
pp. 731-738 ◽  
Author(s):  
D. B. McCorquodale ◽  
R. E. Owen
Keyword(s):  
Megachile Rotundata ◽  
Diploid Males ◽  
Laying Sequence ◽  
Leafcutter Bee ◽  
Nest Usurpation

ALLOZYME VARIATION, RELATEDNESS AMONG PROGENY IN A NEST, AND SEX RATIO IN THE LEAFCUTTER BEE, MEGACHILE ROTUNDATA (FABRICIUS) (HYMENOPTERA: MEGACHILIDAE)

1997 ◽  
Vol 129 (2) ◽  
pp. 211-219 ◽  
Author(s):  
D.B. McCorquodale ◽  
R.E. Owen
Keyword(s):  
Sex Ratio ◽  
Allozyme Variation ◽  
Megachile Rotundata ◽  
Female Progeny ◽  
Nest Parasitism ◽  
Cavity Nesting ◽  
Adult Females ◽  
Two Samples ◽  
Leafcutter Bee ◽  
Nest Usurpation

AbstractWe assessed enzyme variability in a solitary leafcutter bee, Megachile rotundata (Fabricius), and found sufficient variability to compare relatedness among progeny in a nest in two samples: (1) nests with an associated adult female (putative mother) and (2) nests with out-of-sequence male progeny (M. rotundata, like most cavity-nesting solitary aculeates, usually provisions all female cells in a nest before any male cells). Estimates of relatedness from nests with associated adult females were consistent with the progeny in a nest being closely related and the offspring of a single, once-mated female. The relatedness estimates from nests with out-of-sequence males were all much lower, suggesting some combination of nest parasitism, nest usurpation, nest abandonment, and multiply mated females in these nests. The high levels of relatedness among female progeny in the first sample, as expected for full sisters in a haplodiploid system, are considered with respect to the evolution of social behaviour in the Hymenoptera. Besides higher estimates of relatedness, the nests with an associated female also had a lower male:female sex ratio than did nests with out-of-sequence males.

TOXICITY OF INSECTICIDES TO THE ALFALFA LEAFCUTTER BEE, MEGACHILE ROTUNDATA F. (HYMENOPTERA: MEGACHILIDAE), ESTABLISHED BY THREE EVALUATION METHODS

1988 ◽  
Vol 120 (4) ◽  
pp. 297-305 ◽  
Author(s):  
W. A. Charnetski
Keyword(s):  
Petri Dish ◽  
Evaluation Methods ◽  
Laboratory Evaluation ◽  
Evaluation Procedure ◽  
Megachile Rotundata ◽  
Field Cage ◽  
Male And Female ◽  
Significant Difference ◽  
Leafcutter Bee ◽  
Significant Mortality

AbstractThree methods—tube chambers (ventilated and unventilated), petri dish chambers, and field cages—were used to evaluate the toxicity of deltamethrin, trichlorfon, and methoxychlor deposits on alfalfa, Medicago sativa L., to 1- to 7-day-old alfalfa leafcutter bees, Megachile rotundata (F.), 24 and 48 h after exposure. In unventilated tube chambers, all three insecticides were significantly toxic to male bees after 24 and 48 h, but only deltamethrin and trichlorfon were significantly toxic to female bees after 24 h. In ventilated tube chambers, only deltamethrin was significantly toxic by contact and then only to male bees at 24 h. Significant vapor action was observed only for trichlorfon and only in unventilated tube chambers. By the petri dish method, only deltamethrin caused significant mortality to male and female bees. However, bee mortality increased significantly between 24 and 48 h. By the field cage method, there was no significant difference in mortality among treatments and controls within the 24- and 48-h evaluations. Bee mortality in the controls was much higher in the petri dish and field cage methods than in either of the two variations of the tube chamber method. The three evaluation methods are compared and the need for a standardized laboratory evaluation procedure is discussed.

EFFECT OF ENVIRONMENT AND EQUIPMENT ON PRODUCTIVITY OF ALFALFA LEAFCUTTER BEES (HYMENOPTERA: MEGACHILIDAE) IN SOUTHERN ALBERTA, CANADA

1996 ◽  
Vol 128 (1) ◽  
pp. 47-56 ◽  
Author(s):  
K.W. Richards
Keyword(s):  
Environmental Variables ◽  
Total Cell ◽  
Significant Positive Effect ◽  
Megachile Rotundata ◽  
Southern Alberta ◽  
Temperature Heat ◽  
Leafcutter Bee ◽  
Nesting Material ◽  
Higher Temperature ◽  
Positive Effect

AbstractFour indicators of productivity and quality for the alfalfa leafcutter bee, Megachile rotundata (Fab.), were examined over a 3-year period and the influence of different shelter designs, nesting materials, and 34 environmental variables evaluated. A higher percentage of cocoons per total cells was produced in polystyrene nesting material than in pinewood nesting material. Both nesting materials had similar percentages of tunnels capped or containing cells and total numbers of cells per hive. Shelters with conspicuous orientation patterns or silhouettes had more tunnels capped per hive, tunnels with cells, and greater total cell production per hive than did other shelter designs. The time of maximum bee production varied greatly among the 3 years. Many environmental variables, especially those associated with higher temperature, heat units, and mean actual temperature, had a significant positive effect on bee productivity and cell quality. The information contained in this study may help delineate those climatic areas where this valuable alfalfa pollinator can be most effective, and may assist beekeepers in making management decisions that will improve their operations.

IMPACT OF DAMAGE BY THE DRIEDFRUIT MOTH, VITULA EDMANDSAE SERRATILINEELLA (LEPIDOPTERA: PYRALIDAE), A PEST OF THE ALFALFA LEAFCUTTER BEE, MEGACHILE ROTUNDATA (HYMENOPTERA: MEGACHILIDAE)

1983 ◽  
Vol 115 (12) ◽  
pp. 1549-1553 ◽  
Author(s):  
K. W. Richards
Keyword(s):  
Positive Relationship ◽  
Megachile Rotundata ◽  
Wood Material ◽  
Significant Positive Relationship ◽  
Leafcutter Bee ◽  
Lepidoptera Pyralidae ◽  
Nesting Material

AbstractLarvae of the driedfruit moth, Vitula edmandsae serratilineella Ragonot, enter uncapped tunnels in hives of the alfalfa leafcutter bee, Megachile rotundata F., and eat the pollen and nectar provisions of incomplete cells. Significantly more cocoons are destroyed in hives made of pine nesting material than in those made of polystyrene nesting material. However, significantly more tunnel walls are chewed into and through in the polystyrene than in the wood material. A significant positive relationship exists between the number of moth larvae per hive and the number of bee cells produced in that hive. After hives are removed from the field and placed in storage for the winter, most mature larvae leave the tunnels upon completion of feeding and aggregate in spaces between hives.

POSTDIAPAUSE DEVELOPMENT AND ADULT EMERGENCE OF PTEROMALUS VENUSTUS WALKER (HYMENOPTERA: PTEROMALIDAE) DURING ALFALFA LEAFCUTTER BEE INCUBATION

1987 ◽  
Vol 119 (5) ◽  
pp. 491-493 ◽  
Author(s):  
G.H. Whitfield ◽  
K.W. Richards
Keyword(s):  
Adult Emergence ◽  
The United States ◽  
Control Measures ◽  
Western Canada ◽  
Light Traps ◽  
Megachile Rotundata ◽  
Timing Control ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Leafcutter Bee

Pteromalus venustus Walker is the most common parasitoid associated with the alfalfa leafcutter bee, Megachile rotundata (F.), in western Canada (Richards 1984). Leafcutter beekeepers in Canada and the United States use several methods to control P. venustus during incubation of leafcutter bee larvae, including light traps (Hobbs 1973; Richards 1984), dipping the cells in an insecticide (Brindley 1976; Parker 1979), and placing dichlorvos resin strips in the incubator (Hill et al. 1984). Previously we described the influence of temperature on survival and rate of development of the egg, larval, and pupal stages of non-diapausing P. venustus (Whitfield and Richards 1985). Here we report on the influence of temperature on rate of postdiapause development in P. venustus during leafcutter bee incubation and consider the value of this information for timing control measures for this parasitoid.

NUMBER OF INSTARS OF LARVAE OF THE ALFALFA LEAFCUTTER BEE, MEGACHILE ROTUNDATA (F.) (HYMENOPTERA: MEGACHILIDAE)

1987 ◽  
Vol 119 (10) ◽  
pp. 859-865 ◽  
Author(s):  
G.H. Whitfield ◽  
K.W. Richards ◽  
T.M. Kveder
Keyword(s):  
Linear Regression ◽  
Frequency Distribution ◽  
Direct Observation ◽  
Field Studies ◽  
Accurate Method ◽  
Head Capsule ◽  
Physical Injury ◽  
Megachile Rotundata ◽  
Head Capsule Width ◽  
Leafcutter Bee

AbstractThe number of instars of larvae of the alfalfa leafcutter bee, Megachile rotundata (F.), was determined by direct observation, frequency distribution plots, and linear regression of head-capsule measurements. For all three methods, developmental polymorphism was observed; larvae were grouped according to the number of instars. The majority of larvae (77%) had four larval instars and the remainder had five. Mortality of bee larvae, apparently a result of physical injury during measurement of head-capsule width, was high but results were based on data for 259 individuals that completed development to the prepupal (= pharate pupa) stage. Direct observation of larval moults was found to be the only accurate method for determining instar designation but analysis of head-capsule width did describe the number of instars present in a population and provided estimates of head-capsule width for each instar. A morphological key for separation among four instars is presented as a practical alternative for instar determination in field studies.

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