The Impact of Extreme EventsLondon April 25, 2024 Winter-active parasitoids and pollinators: using a metabolomic approach to uncover potential resource competition.
Daisy Scott, David Renault, Harry Siviter, Martin How, Lucy Alford Climate change is leading to milder winters in temperate areas, causing several insect species such as the parasitoid wasp Aphidius ervi and the bumblebee Bombus terrestris to become winter-active, with fewer individuals entering diapause. As floral resources are typically low during winter, implementing strips of winter flowering plants provides supplementary resources for beneficial insect populations, which are currently declining rapidly: a third of wild bee species are in decline, and in some areas 76% of insect biomass has been lost in the last 26 years. This loss is particularly pronounced in agroecosystems, where beneficial insects provide crucial ecosystem services such as pest control and pollination. This has severe ramifications for food production: biological control species provide pest regulation services worth approximately $417 billion worldwide, and pollinators are crucial to 35% of world crop production. Parasitoid wasps are important natural enemies of pests, with Hymenoptera representing 52.2% of species used in augmentative biological control. However, competition over resources can occur between different beneficial insects, impacting the longevity or health of one competitor with implications for the ecosystem services they provide. Due to being nectar-feeding insects, novel competition between parasitoids and bumblebees over floral resources could impact their nutritional status and parasitism rate. By performing cage experiments, this project is investigating whether B. terrestris presence impacts the parasitism rate of A. ervi under winter conditions. Two floral treatments from winter-flowering species are being used alongside a positive and negative control to investigate how sugar composition could impact parasitism rate. Through employing metabolomic profiling and raspberry pi cameras, the project will determine the potential for exploitative and interference competition between the two insect species over floral resources.
0 Comments
Sustainable Agriculture: From Monitoring to ManagementHarpenden September 27, 2023 Potential competition between winter-active parasitoids and pollinators on winter flower strips in agricultural landscapes and the implications for biological control Lucy Alford, Sacha Roudine, Dimitra Valsami, Tiphanie Fontaine-Guenel, Talay Namintraporn, Anaëlle Guedon, Romane Normand, Ludovic Lagneau, Cecile Le Lann, Joan Van Baaren With modern agroecosystems largely homogenous, with low floral diversity, competitive interactions may arise between flower-visiting species, creating antagonisms between ecosystem services (e.g. biological control and pollination). This is particularly true during temperate winters with many insects now losing their diapause overwintering strategy and instead remaining active all year round as a consequence of warming winters. Increased winter activity sees insects vulnerable to the challenging cold temperatures of winter months at a time when wild floral food resources are limited. Flower strips may be implemented during winter months to support flower-visiting insects and enhance ecosystem service provision. Employing field trials conducted in Brittany, France between 2019 and 2021 and laboratory cage experiments, the current study examined the impact of winter flower strips on aphid biological control and the potential for competitive interactions between winter-active parasitoids and pollinators. Results revealed that parasitism rate was not enhanced by the presence of winter flower strips. This lack of effect was not the consequence of pollinator presence, and the current study found no effect of pollinator abundance on parasitism rate. Flower strips may thus be implemented during winter months to support nectar-feeding insects when floral resources are scarce, with no evidence of exploitative competition between pollinators and parasitoids, nor a detrimental impact on biological control provision.
Regenerative Agriculture – Understanding the opportunities and challengesYork April 25-26, 2023 Investigating the link between nutrition and thermal tolerance to inform the design of multifunctional flower strips. Lucy Serjent, Dinushie Gomez, Yuting Huang, Grace Hunnings, Jack Sunderland, Hanyou Zou, Lucy Alford. Climate change is leading to warming winters in temperate regions. As a result, many ectothermic insect species are no longer entering into a winter diapause and are instead remaining winter-active. Increased winter activity will render the insects vulnerable to challenging cold temperatures during a time when floral resources such as nectar and pollen are limited, with implications for the ecosystem services provided by beneficial insects. Cold stress is costly to the individual and, for this reason, nutrition plays a vital role in an individual’s fitness and thus its ability to survive unfavourable temperatures. Consequently, supplementary feeding may enhance the thermal tolerance and thus winter survival of beneficial insects. Supplementary feeding may be achieved via plant diversification schemes with a focus on winter flowering species to provide floral resources to winter-active insects.
One insect increasingly winter-active is the parasitoid wasp and biological control agent Aphidius ervi; a beneficial insect involved in the biological control of aphid pests. Utilising A. ervi as the study organism, the current study investigated the effect of supplementary feeding in the form of winter flowering species commonly employed as winter cover crops, on the thermal tolerance of the wasp and other life history parameters integral to its efficacy as a biological control agent. Ultimately this research contributes towards the development of targeted multifunctional flower strips to support beneficial insect biodiversity including pest control agents in agricultural landscapes and enhance the vital ecosystem services they provide. Shaping the Future for Pollinators - Innovations in Farmed LandscapesSlough-Windsor September 6-8, 2022 Potential competition between parasitoid wasps and winter-active pollinators and the implications for pest control services
Dimitra Valsami, Talay Namintraporn, Ludovic Lagneau, Cecile Le Lann, Joan Van Baaren, Lucy Alford The expansion of modern, chemical-intensive agriculture is regarded as the principal cause of widespread declines in beneficial insects and the valuable ecosystem services they provide, including biological control and pollination. Plant diversification strategies can be put in place within crops to promote pollinators and natural enemies that visit and utilize flowers. However, utilisation of the same floral resources by biological control agents and pollinators could lead to potential competition between these two groups, with negative impacts on the valuable ecosystem services they provide. This is particularly true during temperate winters with many insects now losing their diapause overwintering strategy and instead remaining active all year round as a consequence of warming winters. Increased winter activity sees insects vulnerable to the challenging cold temperatures of winter months in a time when wild floral food resources are limited while some cultivated plants are now flowering. Utilising Bombus terrestris (pollinator) and Aphidius ervi (parasitoid biological control agent) as a study system, we examine potential competition between these two key ecosystem service providers in the presence of winter flowering crops. Employing experimental cages under controlled conditions, the effect of pollinator presence and abundance on natural biological control (as determined by the parasitism rate of aphid pests) was investigated in the presence of winter flowering species. Ultimately, the research contributes towards understanding the potential for plant diversification strategies utilising winter flowering crops to boost natural biological control and ecosystem service provision. XXVI International Congress of EntomologyHelsinki, Finland July 17-22, 2022 Measuring the evolutionary potential of a diapause-avoiding parasitic wasp to climate change
Lucy Alford, Philippe Louâpre, Florence Mougel, Joan van Baaren The earth is currently experiencing rapid changes in climate. In addition to warming temperatures, an increase in the incidence of unpredictable thermal events such as heat / cold waves is also forecast. Species are differently affected by these climatic changes depending on their ability to buffer from and/or to respond to stressful thermal conditions. In areas with mild winters, an increasing number of ectothermic species have lost their diapause strategy, thus remaining active all year. As a consequence, such species are increasingly vulnerable to unpredictable cold stress events. The current study aimed to better understand the evolutionary potential of one such species by estimating heritability of cold tolerance. Using a parental half-sibling breeding design, cold tolerance, morphology and longevity of the parasitoid wasp Aphidius avenae, which has lost its diapause strategy in western France, was investigated and heritability estimates obtained. If the low heritability estimates are indicative of the evolutionary potential of A. avenae cold tolerance, A. avenae may be increasingly reliant on behavioural responses and adaptive phenotypic plasticity to persist in a changing climate, with potential implications for the biological control function they provide. Second International Congress of Biological Control (ICBC2)Online April 26-30, 2021 Could winter flowering cover crops promote competition between parasitoids, hyperparasitoids and winter-active pollinators?
Lucy Alford, Tiphanie Fontaine-Guenel, Sacha Roudine, Cecile Le Lann, Joan van Baaren In temperate climates, many insects are losing their diapause overwintering strategy as a consequence of warming winters and instead are remaining active all year round. Increased winter activity sees insects vulnerable to the challenging cold temperatures of winter months in a time when food availability is limited. This is true of parasitoid wasps of the genus Aphidius; beneficial insects in the natural biological control of cereal aphid pests. To assist in the survival of parasitoids during winter months and to encourage the natural biological control function they perform, farmers may plant winter flowering crops in agricultural landscapes to provide parasitoids with a nectar food resource during the harsh winter months. However, such nectar sources may also be favourable to pollinators (e.g. hoverflies and bees), many of which are also becoming increasingly winter-active. This may lead to potential antagonisms between the ecosystem services of biological control and pollination, with any increased competition potentially undermining the beneficial natural biological control provided by Aphidius parasitoids. Utilising the cereal fields of Brittany, France, we report on an initial study into potential competition between parasitoids and winter-active pollinators. Study insects were sampled from cereal fields at various distances from winter flowering crops and community composition and parasitism rate was determined in the winter of 2019/20. The study will be completed by additional sampling in the winter of 2020/21 and the effect of potential competition on the biological control of cereal aphids determined. |