The Asian vinegar fly Drosophila suzukii (spotted wing Drosophila (SWD)) has emerged as a major invasive insect pest of small and stone fruits in both the Americas and Europe since the late 2000s. While research efforts have rapidly progressed in Asia, North America, and Europe over the past 5 years, important new insights may be gained in comparing and contrasting findings across the regions affected by SWD. In this review, we explore common themes in the invasion biology of SWD by examining (1) its biology and current pest status in endemic and recently invaded regions; (2) current efforts and future research needs for the development of predictive models for its geographic expansion; and (3) prospects for both natural and classical (=importation) biological control of SWD in invaded habitats, with emphasis on the role of hymenopteran parasitoids. We conclude that particularly fruitful areas of research should include fundamental studies of its overwintering, host-use, and dispersal capa- bilities; as well as applied studies of alternative, cost-ef- fective management techniques to complement insecticide use within the integrated pest management framework. Finally, we emphasize that outreach efforts are critical to effective SWD management by highlighting successful

/pdf/invasion-biology-of-spotted-wing-drosophila-drosophila-59xpp2s3ts.pdf

Invasion biology of spotted wing Drosophila (Drosophila suzukii): a global perspective and future priorities

Two novel and simple mathematical models of arthropod temperature-dependent development are proposed. These models are easy to use and have 3 (equation 1) and 4 (equation 2) ecologically meaningful parameters, respectively. Each parameter can be estimated using nonlinear regression. These models were used to compare developmental rates at constant temperatures for our own experiments on Lobesia botrana (Dennis & Schiffermuller) and for data from 6 insect species described (a total of 13 stages). In all cases, we obtained an accurate nonlinear description of the rate of development against temperature given by the adjusted R 2 ([Kvalseth, 1985][1]). The adjusted R 2 calculated extended from 0.86 to 0.99 and were identical for our equations 1 and 2. In all cases, equation 2 provided the lowest residual sums of squares. The models gave upper T L and lower T temperature threshold estimations, and the estimations obtained were better by using equation 1 rather equation 2. Confidence intervals for each parameter were given and a comparison between estimated and observed temperature thresholds were presented.

 [1]: #ref-11

A Novel Rate Model of Temperature-Dependent Development for Arthropods

The ecology of mosquito vectors and malaria parasites affect the incidence, seasonal transmission and geographical range of malaria. Most malaria models to date assume constant or linear responses of mosquito and parasite life-history traits to temperature, predicting optimal transmission at 31 °C. These models are at odds with field observations of transmission dating back nearly a century. We build a model with more realistic ecological assumptions about the thermal physiology of insects. Our model, which includes empirically derived nonlinear thermal responses, predicts optimal malaria transmission at 25 ° C( 6°C lower than previous models). Moreover, the model predicts that transmission decreases dramatically at temperatures > 28 °C, altering predictions about how climate change will affect malaria. A large data set on malaria transmission risk in Africa validates both the 25 °C optimum and the decline above 28 °C. Using these more accurate nonlinear thermal-response models will aid in understanding the effects of current and future temperature regimes on disease transmission.

/pdf/optimal-temperature-for-malaria-transmission-is-dramatically-47ra14blcf.pdf

Optimal temperature for malaria transmission is dramatically lower than previously predicted.

The glucosinolates are a large group of sulphur-containing compounds which occur in all the economically important varieties of Brassica vegetable. Their common structure comprises a β-D-thioglucose group, a sulphonated oxime moiety and a variable side-chain derived from methionine, tryptophan or phenylalanine. When the plant tissue is damaged the glucosinolates are hydrolysed by the endogenous enzyme ‘myrosinase’ (thioglucoside glycohydrolase EC 3:2:3:1), to release a range of breakdown products including the bitter, biologically active isothiocyanates. Although these compounds exert antinutritional effects in animals there is also substantial evidence that they are the principal source of anticarcinogenic activity in Brassica vegetables, and this provides a strong motive for the manipulation of glucosinolate levels in vegetables for human consumption. This review provides an overview of the evidence for a beneficial role for glucosinolates in human health, and describes the current state of knowledge regarding the genetics and biosynthesis of glucosinolates, their chemical analysis, their behaviour during cooking and processing, and their bioavailability to humans. As the genetic basis of glucosinolate biosynthesis becomes more apparent, and tools for marker-assisted plant breeding become more available, the selective breeding of horticultural brassicas with different levels and types of glucosinolates, whether by conventional means or genetic manipulation, is becoming a practical possibility. However before this strategy becomes commercially viable, the health benefits of glucosinolates for human beings must be unequivocally established.

© 2000 Society of Chemical Industry

The nutritional significance, biosynthesis and bioavailability of glucosinolates in human foods

The incubation period for malaria parasites within the mosquito is exquisitely temperature-sensitive, so that temperature is a major determinant of malaria risk. Epidemiological models are increasingly used to guide allocation of disease control resources and to assess the likely impact of climate change on global malaria burdens. Temperature-based malaria transmission is generally incorporated into these models using mean monthly temperatures, yet temperatures fluctuate throughout the diurnal cycle. Here we use a thermodynamic malaria development model to demonstrate that temperature fluctuation can substantially alter the incubation period of the parasite, and hence malaria transmission rates. We find that, in general, temperature fluctuation reduces the impact of increases in mean temperature. Diurnal temperature fluctuation around means >21°C slows parasite development compared with constant temperatures, whereas fluctuation around <21°C speeds development. Consequently, models which ignore diurnal variation overestimate malaria risk in warmer environments and underestimate risk in cooler environments. To illustrate the implications further, we explore the influence of diurnal temperature fluctuation on malaria transmission at a site in the Kenyan Highlands. Based on local meteorological data, we find that the annual epidemics of malaria at this site cannot be explained without invoking the influence of diurnal temperature fluctuation. Moreover, while temperature fluctuation reduces the relative influence of a subtle warming trend apparent over the last 20 years, it nonetheless makes the effects biologically more significant. Such effects of short-term temperature fluctuations have not previously been considered but are central to understanding current malaria transmission and the consequences of climate change.

https://www.pnas.org/content/pnas/106/33/13844.full.pdf

Understanding the link between malaria risk and climate.

Effects of temperature on egg, larval, and pupal developmental times of the grape berry moth, Lobesia botrana Dennis & Schiffermuller, were examined at several constant temperatures ranging from 8 to 34°C by 2°C increments, with a relative humidity of 65% and a photoperiod of 16:8 (L:D) h. Optimal temperatures for development ranged from 28 to 30°C. The lower and upper limits occurred between 8 and 12°C and between 32 and 34°C, respectively. The experimental conditions covering the complete temperature range for each stage allowed us to apply the data to 5 published equations describing the effect of constant temperatures on developmental rates of various insects. Criteria of choice from the literature were used to evaluate models and to select the most suitable equation for each developmental stage of L. botrana .

Comparison of Temperature-Dependent Growth Models with the Development of Lobesia botrana (Lepidoptera: Tortricidae)

In vineyards, larvae of the grape berry moth ( Lobesia botrana ) favour the development of the grey mould fungus Botrytis cinerea  To study the possibility of a mutualistic relationship between these organisms, we investigated the effects of the fungus on the development and oviposition behaviour of the insect Larvae were reared on whole plants infected or uninfected with the fungus, or on an artificial diet containing either infected grape berries or the mycelium The presence of the fungus consistently led to a reduction in the duration of insect development (4–6 d) and mortality (20–67 %) The fecundity increased from 12 to 76 % Moreover, the fact that the females laid eggs preferentially on fungus-infected grape berries confirms the mutualistic association between these organisms The fungus alone contributed to the positive effects We showed the existence of a mutualistic relationship between the two organisms which are both damaging to vineyards

Mutualism between a phytopathogenic fungus (Botrytis cinerea) and a vineyard pest (Lobesia botrana). Positive effects on insect development and oviposition behaviour

In vineyards, larvae of Lobesia botrana (Denis and Schiffermuller) (Lepidoptera: Tortricidae) and Botrytis cinerea (Persoon: Fries) often occur together. This study was carried out to establish whether first instar larvae are attracted by the fungus. Olfactory and gustatory responses of larvae to the fungus were investigated on grape berry clusters (Vitis vinifera) and in two types of olfactometer. In clusters infected partly by B. cinerea, 82% of first instar larvae settled where berries had been infected. In the olfactometers, first instar larvae detected and discriminated between two tested foods. They significantly preferred synthetic media or grape berries (cv., 'Alphonse Lavallee' or 'Cabernet Sauvignon') infected with B. cinerea to non-infected controls. The olfactory response led to 62.2% to 72.6% of the first instar larvae attracted by the fungus and the association of olfactory with gustatory responses resulted in similar rates (64. 1 % to 81.6%). So, the larvae were most attracted by synthetic media or grape berries infected by the fungus as compared to the controls. Olfaction appears to be the main sense involved in this attraction process.

Pascale Pracros

Papers

A Novel Rate Model of Temperature-Dependent Development for Arthropods

Comparison of Temperature-Dependent Growth Models with the Development of Lobesia botrana (Lepidoptera: Tortricidae)

Mutualism between a phytopathogenic fungus (Botrytis cinerea) and a vineyard pest (Lobesia botrana). Positive effects on insect development and oviposition behaviour

Olfactory and gustatory behaviour by larvae of Lobesia botrana in response to Botrytis cinerea

Effects on growth and respiration due to the ingestion of the rapeseed meal glucosinolates in young larvae of Tenebrio molitor