Metabolic and transcriptomic characterization of summer and winter dormancy in the solitary bee, Osmia lignaria.

The solitary bee Osmia lignaria is a native pollinator in North America with growing economic importance. The life cycle of O. lignaria provides a unique opportunity to compare the physiological and molecular mechanisms underlying two ecologically contrasting dormancies within the same species.

Comparison of the Chemical Compositions of the Cuticle and Dufour's Gland of Two Solitary Bee Species from Laboratory and Field Conditions.

Species-specific biochemistry, morphology, and function of the Dufour's gland have been investigated for social bees and some non-social bee families. Most of the solitary bees previously examined are ground-nesting bees that use Dufour's gland secretions to line brood chambers. This study examines the chemistry of the cuticle and Dufour's gland of cavity-nesting Megachile rotundata and Osmia lignaria, which are species managed for crop pollination.

Optimizing Fluctuating Thermal Regime Storage of Developing Megachile rotundata (Hymenoptera: Megachilidae).

The alfalfa leafcutting bee, Megachile rotundata (F.), is the primary pollinator for alfalfa seed production in North America. Under current management practice, developing pupae are incubated at 29-30°C until the adults emerge for pollination.

How Hives Collapse: Allee Effects, Ecological Resilience, and the Honey Bee.

We construct a mathematical model to quantify the loss of resilience in collapsing honey bee colonies due to the presence of a strong Allee effect. In the model, recruitment and mortality of adult bees have substantial social components, with recruitment enhanced and mortality reduced by additional adult bee numbers. The result is an Allee effect, a net per-individual rate of hive increase that increases as a function of adult bee numbers.

Exposure to Suboptimal Temperatures during Metamorphosis Reveals a Critical Developmental Window in the Solitary Bee, Megachile rotundata.

Metamorphosis is an important developmental stage for holometabolous insects, during which adult morphology and physiology are established. Proper development relies on optimal body temperatures, and natural ambient temperature (Ta) fluctuations, especially in spring or in northern latitudes, could result in interruptions to development. It is unclear how low-Ta exposure may affect insects that are actively developing.

Thermoperiodism Synchronizes Emergence in the Alfalfa Leafcutting Bee (Hymenoptera: Megachilidae).

Alfalfa seed production in the northwestern United States and western Canada is heavily dependent upon the pollinating services of Megachile rotundata (F.) (Hymenoptera: Megachilidae). M.

Social evolution. Genomic signatures of evolutionary transitions from solitary to group living.

The evolution of eusociality is one of the major transitions in evolution, but the underlying genomic changes are unknown. We compared the genomes of 10 bee species that vary in social complexity, representing multiple independent transitions in social evolution, and report three major findings. First, many important genes show evidence of neutral evolution as a consequence of relaxed selection with increasing social complexity.

Transcriptional responses to fluctuating thermal regimes underpinning differences in survival in the solitary bee Megachile rotundata.

The transcriptional responses of insects to long-term, ecologically relevant temperature stress are poorly understood. Long-term exposure to low temperatures, commonly referred to as chilling, can lead to physiological effects collectively known as chill injury. Periodically increasing temperatures during long-term chilling has been shown to increase survival in many insects.

Cell position during larval development affects postdiapause development in Megachile rotundata (Hymenoptera: Megachilidae).

Megachile rotundata (F.) (Hymenoptera: Megachilidae) is the primary pollinator of alfalfa in the northwestern United States and western Canada and provides pollination services for onion, carrot, hybrid canola, various legumes, and other specialty crops. M.

Changes in respiratory structure and function during post-diapause development in the alfalfa leafcutting bee, Megachile rotundata.

Megachile rotundata, the alfalfa leafcutting bee, is a solitary, cavity-nesting bee. M. rotundata develop from eggs laid inside brood cells constructed from leaf pieces and placed in series in an existing cavity.

Nest marking behavior and chemical composition of olfactory cues involved in nest recognition in Megachile rotundata.

In-nest observations of the solitary bee, Megachile rotundata (F.), revealed that nesting females apply olfactory cues to nests for nest recognition. On their way in and out of the nest, females drag the abdomen along the entire length of the nest, and sometimes deposit fluid droplets from the tip of the abdomen.

A fluctuating thermal regime improves long-term survival of quiescent prepupal Megachile rotundata (Hymenoptera: Megachilidae).

The alfalfa leafcutting bee Megachile rotundata (F.) is the primary pollinator for alfalfa seed production. Under standard management conditions, the alfalfa leafcutting bee develops to the diapausing prepupal stage under field conditions, after which they are cold-stored at a static temperature until the following spring, when temperatures are raised and development resumes.

Duration of prepupal summer dormancy regulates synchronization of adult diapause with winter temperatures in bees of the genus Osmia.

Osmia (Osmia) bees are strictly univoltine and winter as diapausing adults. In these species, the timing of adult eclosion with the onset of wintering conditions is critical, because adults exposed to long pre-wintering periods show increased lipid loss and winter mortality. Populations from warm areas fly in February-March and are exposed to longer growth seasons than populations from colder areas, which fly in April-May.

Duration and frequency of a high temperature pulse affect survival of emergence-ready Megachile rotundata (Hymenoptera: Megachilidae) during low-temperature incubation.

Synchronizing Megachile rotundata (F.) nesting activity with alfalfa bloom is essential for ensuring optimal pollination for alfalfa seed production. This is achieved by timing the initiation of spring bee incubation so that adults will emerge -2 wk before peak bloom.

The long summer: pre-wintering temperatures affect metabolic expenditure and winter survival in a solitary bee.

The impact of climate change on insect populations depends on specific life cycle traits and physiological adaptations. The solitary bee Osmia lignaria winters as a pre-emergent adult, and requires a period of cold temperature for winter diapause completion. It is a univoltine species, and diapause induction does not depend on photoperiod.

A fluctuating thermal regime improves survival of cold-mediated delayed emergence in developing Megachile rotundata (Hymenoptera: Megachilidae).

A significant concern in the commercial application of the alfalfa leafcutting bee, Megachile rotundata (F.) (Hymenoptera: Megachilidae), for pollination is synchronizing bee emergence and activity with peak crop bloom. Previous studies have demonstrated that the commercial spring incubation of this species can be successfully interrupted by low temperature incubation, thereby slowing development and giving producers flexibility in timing emergence to weather conditions or crop bloom.

Cyclic CO(2) emissions during the high temperature pulse of fluctuating thermal regime in eye-pigmented pupae of Megachile rotundata.

Megachile rotundata (Hymenoptera: Megachilidae), the primary pollinator used in alfalfa seed production, may need to be exposed to low-temperature storage to slow the insects' development to better match spring emergence with the alfalfa bloom. It has been demonstrated that using a fluctuating thermal regime (FTR) improves the tolerance of pupae to low temperatures. Carbon dioxide emission rates were compared between four different FTRs, all with a base temperature of 6°C and a daily high-temperature pulse.

Timing of eclosion affects diapause development, fat body consumption and longevity in Osmia lignaria, a univoltine, adult-wintering solitary bee.

Most insects from temperate areas enter diapause ahead of winter. Species diapausing in a feeding stage and accumulating metabolic reserves during permissive pre-wintering conditions are expected to enter diapause shortly before the onset of winter. In contrast, species diapausing in a non-feeding stage are expected to lower their metabolism as soon as possible to avoid excessive consumption of metabolic reserves.

Interrupted incubation and short-term storage of the alfalfa pollinator Megachile rotundata (Hymenoptera: Megachilidae): a potential tool for synchronizing bees with bloom.

A useful technique for synchronizing pollinators with the alfalfa, Medicago savita L. (Fabaceae), bloom is to interrupt the late spring incubation of developing bee pupae and pharate adults of Megachile rotundata (F.) (Hymenoptera: Megachilidae) with short-term low-temperature storage.

Cuticular lipids of female solitary bees, Osmia lignaria Say and Megachile rotundata (F.) (Hymenoptera: Megachilidae).

The cuticular lipids of the cavity-nesting adult female solitary bees, Osmia lignaria Say and Megachile rotundata (F.) (Hymenoptera: Megachilidae), were analyzed by gas chromatography (GC) and combined GC-mass spectrometry. The cuticular lipids of these female bees are mainly consisted of hydrocarbons.

Effects of three-dimensional and color patterns on nest location and progeny mortality in alfalfa leafcutting bee (Hymenoptera: Megachilidae).

ABSTRACT In alfalfa, Medicago sativa L., seed production where high bee densities are released, alfalfa leafcutting bee, Megachile rotundata (F.) (Hymenoptera: Megachilidae), females may enter several nesting holes before locating their nests.

Bee population returns and cherry yields in an orchard pollinated with Osmia lignaria (Hymenoptera: Megachilidae).

During 1998-2003, we used populations of the solitary bee Osmia lignaria Say to pollinate a commercial sweet cherry orchard in northern Utah. Bee densities released each year ranged from 1290 to 1857 females/ha, with approximately twice as many males. Female progeny produced each year were greater than parental populations released, except in 2003, when nesting was poor due to bird predation.

Alfalfa leafcutting bee population dynamics, flower availability, and pollination rates in two Oregon alfalfa fields.

Since the 1970s, it has become increasingly difficult for U.S. alfalfa seed producers to maintain Megachile rotundata (F.

Characterization of triacylglycerols from overwintering prepupae of the alfalfa pollinator Megachile rotundata (Hymenoptera: Megachilidae).

Alfalfa leafcutting bees, Megachile rotundata (F.), overwinter as prepupae. The internal lipids were extracted from prepupae that had been wintered at 4 degrees C for 7 months.