Biology subjects

Austin, A. J.

Publications and source records attributed to Austin, A. J..

3 recordsLinked to original sources

bioRxiv2019

Plugging the hunger gap: Organic farming supports more abundant nutritional resources for bees at critical periods

O_LIUnderstanding the decline in bee populations and their plant mutualists is of paramount concern for ecosystem health, as well as our future food security. Intensive farming practices are one of the major drivers behind such declines. Organic farming is one of the principal alternatives to conventional practices yet the evidence for its effects are mixed, with some studies showing limited benefits. C_LIO_LIWe conducted bee and floral surveys on 10 paired organic and conventional farms across Yorkshire, UK, to investigate how farming practice influenced the abundance, richness and community composition of bees and flowering plants. C_LIO_LIFirstly, we found that species richness for flowering plants and bees was similar across organic and conventional farms. Floral composition differed between organic and conventional farms with the greatest differences seen in May and June, whereas bee community composition was similar among farming practices. C_LIO_LISecondly, both bee and floral abundance were higher in organic farms. Peaks in floral abundance, and corresponding bee abundance, occurred in particular months, most notably in July, with abundance during the rest of the season being similar across both farming practices. C_LIO_LISynthesis and applications: Our results suggest that higher floral availability on organic farms corresponds with increased bee abundance. Of particular importance was the higher floral abundance during spring, in the pollinator hungry gap, where floral resources are traditionally scarce. However, conventional farms performed comparably to organic farms across the rest of the season, as well as showing similar levels of species richness, diversity and species composition for both flowering plants and bees. We suggest that targeted management on conventional farms, aimed at boosting floral abundance in the spring, when floral abundance is low, could allow conventional farms to make up the shortfall. Additionally, focusing on increasing the diversity of flowering plants, in terms of both phenology and nutritional composition, for both adult bees and their larvae, could improve bee community diversity across both farming systems. C_LI

ecology↗

bioRxiv2019

Differential effects of farming practice on cuckoo bumblebee communities in relation to their hosts

O_LIBees are important for vital pollination of wild and crop plants, but are in decline worldwide. Intensification of agriculture is a major driver of bee decline. Organic farming practices are designed to limit environmental impacts of agriculture and can increase bee abundance and species diversity. However, studies have been heavily focused towards some guilds of bees, overlooking others. This includes social brood parasites, cuckoo bumblebees, an understudied bee lineage. Little is known about bumblebee host and cuckoo population dynamics, and the effects of farming practice on cuckoo bumblebees have never previously been evaluated.\nC_LIO_LITo compare the effects of farming practice (organic vs conventional) on the abundance, species diversity, and community dissimilarity of cuckoo bumblebees and their hosts, we compared host and cuckoo community metrics across ten matched pairs of organic and conventional farms in Yorkshire, UK.\nC_LIO_LIAs found by many previous studies, host bumblebees were more abundant on organic farms than on conventional farms. Despite this, cuckoo bumblebees were equally abundant on both farm types. Contrary to prediction, community dissimilarity and species diversity were unaffected by farm type for both host and cuckoo communities.\nC_LIO_LISynthesis and applications: Results suggest that cuckoo bumblebee community metrics are not solely driven by host community metrics, and that cuckoos may respond differently from their hosts to differences among farming practices. This could, in turn, indicate that a unified management practice is not sufficient to conserve all bumblebee species.\nC_LI

ecology↗

bioRxiv2018

The geometry of dependence: solitary bee larvae prioritize carbohydrate over protein in parentally provided pollen

O_LIMost organisms must regulate their nutritional intake in an environment full of complex food choices. While this process is well understood for self-sufficient organisms, dependent offspring, such as bee larvae, in practice have limited food choices because food is provided by parents. Nutrient balancing may therefore be achieved by offspring, by parents on offsprings behalf, or by both, whether cooperatively or in conflict. C_LIO_LIWe used the Geometric Framework to investigate the capacity of dependent larval mason bees (Osmia bicornis) to regulate their intake of protein and carbohydrate. Female Osmia seal eggs individually inside cells they have provisioned with pollen, and have no contact with developing offspring, allowing offspring choices to be studied in isolation. Herbivorous insect larvae are typically expected to balance protein and carbohydrate to maximise growth and reproduction. C_LIO_LIContrary to prediction, carbohydrate and not protein mediated both growth and survival to pupation. Accordingly, larvae prioritised maintaining a constant intake of carbohydrate and self-selected a relatively carbohydrate biased diet compared to other hymenopterans, while tolerating wide excesses and deficiencies of protein, rendering them potentially vulnerable to dietary change or manipulation. Reasons for prioritising carbohydrate may include (1) the relative abundance of protein in their normal pollen diet, (2) the relative paucity of nectar in parental provisions making carbohydrate a scarce resource, or (3) the requirement for diapause for all O. bicornis larvae. Larvae were intolerant of moderate dietary dilution, likely reflecting an evolutionary history of nutrient-dense food. C_LIO_LIOur results demonstrate that dependent offspring can remain active participants in balancing their own nutrients even when sedentary, and, moreover, even in mass provisioning systems where parents and offspring have no physical contact. Research should now focus on whether and how evolutionary interests of parent and dependent offspring coincide or conflict with respect to food composition, and the implications for species resilience to changing environments. C_LI

animal behavior and cognition↗