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.

Some Mechanisms That Affect the Sex Ratio of Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae) Reared From Superparasitized Housefly Pupae

1966 ◽  
Vol 98 (6) ◽  
pp. 645-653 ◽  
Author(s):  
H. G. Wylie
Keyword(s):  
Sex Ratio ◽  
Musca Domestica ◽  
Nasonia Vitripennis ◽  
Female Progeny ◽  
Male Progeny ◽  
Adult Females

AbstractFemale Nasonia vitripennis (Walk.) parasitizing housefly (Musca domestica L.) pupae produce a smaller percentage of female progeny at high parasite:host ratios than at lower ones because they fertilize a smaller percentage of their eggs (in this species unfertilized eggs produce male progeny), and because more female than male larvae die on superparasitized hosts. The adult females fertilize relatively fewer eggs at high than at low parasite:host ratios for two reasons. First, they encounter relatively more previously attacked hosts, on which they lay a smaller percentage of fertilized eggs than on previously unattacked ones; second, they more often encounter other female parasites while ovipositing, and this interference reduces the percentage of fertilized eggs they lay.

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.

scholarly journals Response of a remnant marmot population to habitat enhancement yields insights into marmot ecology

2020 ◽  
Vol 101 (3) ◽  
pp. 658-669
Author(s):  
Melissa J Reynolds-Hogland ◽  
Alan B Ramsey ◽  
August T Seward ◽  
Kristine L Pilgrim ◽  
Cory Engkjer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Young Population ◽  
Marmota Flaviventris ◽  
Livestock Management ◽  
Adult Females ◽  
Capture Recapture ◽  
Geographic Expansion ◽  
Age Structured ◽  
Habitat Enhancement ◽  
Remnant Population

Abstract We evaluated the response of a remnant population of yellow-bellied marmots (Marmota flaviventris) to targeted habitat enhancement in an ecological system that had been degraded during ~100 years of intensive livestock management, including marmot eradication. We used capture-recapture data and a novel use of a multistate framework to evaluate geographic expansion of the marmot population pre- and post-habitat enhancement. We also estimated age-structured survival, reproduction, and sex ratios. The marmot population appeared to respond positively to new habitat opportunities created by habitat enhancement: the number of marmots captured increased from three marmots pre-habitat enhancement to 54 (28 adults and yearlings, 26 young) post-habitat enhancement at the end of the study. Marmots expanded geographically by transitioning into habitat-enhanced areas, and adult females occupied and reproduced in all habitat-enhanced areas. The sex ratio of the young population in 2019 was strongly female-biased, which may have been influenced by poor body condition of breeding females owing to unusually prolonged snow cover that year. Adult and yearling survival were within the range of that reported for colonial adults and yearlings in Colorado. Our results suggest that active habitat enhancement can assist in the recovery of marmot populations in systems where marmots historically existed.

Moult, Movements, Age and Sex Composition of Mountain Duck, Tadorna tadornoides, Banded at Lake George, N.S.W

1976 ◽  
Vol 3 (2) ◽  
pp. 173 ◽  
Author(s):  
JL McKean ◽  
LW Braithwaite
Keyword(s):  
Sex Ratio ◽  
Age Structure ◽  
New South ◽  
Sex Composition ◽  
South Wales ◽  
Two Samples ◽  
Significant Difference ◽  
Moult Migration ◽  
Lake George ◽  
Age And Sex

Two samples of mountain ducks totalling 1001 birds were trapped and banded at Lake George,N.S.W. A highly significant difference in age structure between the two samples, taken in January 1965 and in February 1970, may be related to major differences in rainfall for the year preceding each sample. The sex ratio was markedly biased in favour of females. Recoveries of birds were nearly all to the south and west and 300-700 km from the banding site. Fully 99 % of recoveries were in States other than New South Wales. Examination of one sample of 679 mountain ducks for moult of primary and secondary wing feathers showed that approximately one-third of the adults were moulting. It was concluded that the birds were possibly normal residents of the region in which most recoveries occurred, and that they make an annual moult migration to Lake George.

scholarly journals Description and Biological Studies of a New Species of Metaphycus Mercet, 1917 (Hymenoptera: Encyrtidae), A Parasitoid of Capulinia linarosae Kondo & Gullan

2019 ◽  
Vol 11 ◽  
pp. 117954331985796
Author(s):  
Dorys T Chirinos ◽  
Takumasa Kondo
Keyword(s):  
Sex Ratio ◽  
Insect Pest ◽  
Morphological Characteristics ◽  
Psidium Guajava ◽  
Adult Longevity ◽  
Single Male ◽  
Adult Females ◽  
Biological Studies ◽  
Control Programmes ◽  
Baseline Information

The guava cottony scale, Capulinia linarosae Kondo & Gullan (Hemiptera: Eriococcidae), is an important pest of guava, Psidium guajava L. (Myrtaceae) in northern Colombia and Venezuela. A species of Metaphycus (Hymenoptera: Encyrtidae) is the only known primary parasitoid associated with this insect pest. The parasitoid is herein described as M. marensis Chirinos & Kondo, sp. nov., based on morphological characteristics of the adult female and male. Biological studies on adult longevity, fecundity, host preference, and sex ratio were conducted. The maximum longevity of the female and the male were 8.0 and 6.5 days, respectively, when fed with diluted honey. On average, a fed mated female laid approximately 40 eggs. Adult females of M. marensis were shown to prefer to parasitize 11- to 15-day-old adult females of C. linarosae and do not parasitize first-instar nymphs of the host eriococcid. The female-to-male sex ratio of the parasitoid was 2.24: 1. When ovipositing females of M. marensis were given only small-sized individuals (second-instar nymphs) of C. linarosae, generally the resulting progeny was a single male wasp. This parasitoid species has arrhenotokous reproduction and is a facultative gregarious parasitoid. These results show a short adult longevity, as well as a relatively low fecundity of the female compared with studies conducted on other Metaphycus species. This study provides essential baseline information for future biological control programmes for C. linarosae.

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.

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