Ecosystem services on horticulture: value of native mirid species

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Contrasting Phenotypic Variability of Life-History Traits of Two Feral Populations of Macrolophus pygmaeus (Hemiptera: Miridae) under Two Alternative Diets

Publication . Borges, Isabel; Oliveira, Luísa; Durão, Ana C.; Arruda, Patrícia; Figueiredo, Elisabete; Franco, José Carlos; Lucas, Eric; Soares, António O.

Tuta absoluta is a major pest attacking tomato crops. This invasive species emerged in Europe (Spain) in 2006, and 3 years later it spread to Portugal. In 2009/2010, it was recorded for the first time in the Azores archipelago. Macrolophus pygmaeus is a predator widely used as biological control agent against the tomato leaf miner. This study contrasted the life-history traits and population growth parameters of two feral populations of M. pygmaeus, one from Portugal mainland and one from the Azores archipelago. The predators were tested on single prey diet, either of Ephestia kuehniella eggs, a factitious prey used for mass rearing of mirids, or T. absoluta eggs. We predicted that populations would express differences in its phenotypic characteristics, with the Azorean population displaying low performance due to likely low genetic diversity, as expected for insular populations. Our results revealed the inexistence of phenotypic differences in several life history traits, such as immature developmental time, female longevity, males’ body weight and sex ratio. Contrary to our predictions, traits with direct impact on fitness, such as lifetime fertility (95.78 ± 14.23 vs. 61.38 ± 13.52 nymphs), explain better performances for the population of the Azores. Azorean M. pygmaeus females were larger, matured earlier and reproduced at a higher rate for longer periods, than mainland females. Therefore, population growth parameters show a positive advantage for the population of the Azores, fed on T. absoluta (time required for doubling the population Azores, Ek: 8.42 ± 0.50, Ta: 5.76 ± 0.31 and mainland, Ek: 10.88 ± 1.94, Ta: 12.07 ± 3.15). Biological performance of M. pygmaeus was similar when fed with T. absoluta or E. kuehniella that could be beneficial both to optimize mass production of the predator and biological control of the pest. Our results are discussed as well in a fundamental perspective, seeking if differences in biological performance can be explained by lower genetic diversity driven by geographic isolation.

2023-01Journal article

Open access

Prey consumption and conversion efficiency in females of two feral populations of Macrolophus pygmaeus, a biocontrol agent of Tuta absoluta

Publication . Borges, Isabel; Oliveira, Luísa; Barbosa ·, Francisco; Figueiredo, Elisabete; Franco, José Carlos; Durão, Ana C.; Soares, António Onofre

Macrolophus pygmaeus (Rambur, 1839) (Hemiptera: Miridae) is a polyphagous predator used in programs of biological control and integrated pest management as a natural enemy against small arthropod pests including whiteflies, thrips, spi- der mites and aphid. This mirid is also successfully mass reared under factitious prey for commercial purposes. In the present study we assessed and com- pared the prey consumption, weight gain and conver- sion efficiency in females of two populations of M. pygmaeus, from mainland Portugal and the Azores, fed on single prey diets of Ephestia kuehniella Zel- ler (Lepidoptera: Pyralidae) eggs, or Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) eggs. We found that female’s prey consumption on eggs of T. abso- luta was higher than that of E. kuehniella, presum- ably due to the comparative size/amount of biomass of the eggs. Translating prey consumption in biomass ingested, we only found a significant difference for consumption on E. kuehniella eggs by M. pygmaeus from the Azores. Despite the smaller size of females from the Azores, they were able to consume more prey and ultimately reaching a similar body weight and conversion efficiency compared with females from mainland, independently of the prey provided. Our results are in line with a previous study, showing differences in the life-history traits of M. pygmaeus from mainland Portugal and Azorean populations fed on alternative prey. From an applied perspective, our results are a contribution to the decision-making on the use of the most effective biocontrol agents for different prey and/or agroecosystem contexts.

2024-04Journal article

Open access

Half Friend, Half Enemy? Comparative Phytophagy between Two Dicyphini Species (Hemiptera: Miridae)

Publication . Souto, Paula; Abraços-Duarte, Gonçalo; Borges da Silva, Elsa; Figueiredo, Elisabete

Despite their importance as biological control agents, zoophytophagous dicyphine mirids can produce economically important damage. We evaluated the phytophagy and potential impact on tomato plants of Dicyphus cerastii and Nesidiocoris tenuis. We developed a study in three parts: (i) a semi-field trial to characterize the type of plant damage produced by these species on caged tomato plants; (ii) a laboratory experiment to assess the effect of fruit ripeness, mirid age, and prey availability on feeding injuries on fruit; and (iii) a laboratory assay to compare the position of both species on either fruit or plants, over time. Both species produced plant damage, however, although both species produced scar punctures on leaves and necrotic patches on petioles, only N. tenuis produced necrotic rings. Both species caused flower abortion at a similar level. Overall, N. tenuis females produced more damage to tomato fruit than D. cerastii. There was an increased frequency of D. cerastii females found on the plants over time, which did not happen with N. tenuis. Our results suggested that, although D. cerastii caused less damage to fruit than N. tenuis, it still fed on them and could cause floral abortion, which requires field evaluation and caution in its use in biological control strategies

2022Journal article

Open access

Avaliação de taxas de predação e de resposta funcional de Dicyphus cerastii Wagner (Hemiptera: Miridae) sobre pragas de hortícolas protegidas

Publication . Ramos, Susana Filipa Lucas; Figueiredo, Elisabete

A cultura do tomate é uma das principais culturas hortícolas/horto-industriais em Portugal. Nesta cultura, existe, frequentemente, dificuldade em controlar pragas, como a traça-do-tomateiro e mosquinha branca. Dicyphus cerastii Wagner é um inseto autóctone que frequentemente coloniza de forma espontânea a cultura do tomateiro, e sabe-se que preda traça-do-tomateiro e mosquinha branca. No entanto, existe pouco conhecimento em relação a esta espécie de mirídeo. Esta dissertação procura esclarecer o papel de D. cerastii como agente de controlo biológico. Para isso, identificou-se o tipo de resposta funcional e avaliaram-se taxas de predação sobre diferentes presas. A avaliação da resposta funcional e de taxas de predação é importante no caso de se pretender fazer largadas deste inimigo natural. Foi contabilizada a predação de fêmeas adultas de D. cerastii sobre quatro espécies de presa diferentes: traça-do-tomateiro [Tuta absoluta (Meyrick)], mosquinha-branca-do-tabaco [Bemisia tabaci (Genn.)], afídeo-verde-do-pessegueiro (Myzus persicae Sulzer) e traça-da-farinha (Ephestia kuehniella Zeller). Para cada presa, foram consideradas modalidades correspondentes a densidades diferentes da presa. Os ensaios decorreram a 25 ± 1 °C, 65 ± 5% de humidade relativa e 14h de fotoperíodo por um período de 24h. Dicyphus cerastii apresentou valores médios de consumo elevados e descreveu uma resposta funcional de tipo II sobre todas as espécies-presa. O seu consumo máximo estimado foi de 51 ninfas de M. persicae, 222 ovos de T. absoluta, 164 ovos de E. kuehniella e 112 ninfas de B. tabaci. Estes valores são mais elevados que os observados para outras espécies de mirídeos predadores, o que torna D. cerastii um agente de controlo biológico potencialmente interessante

2020Master thesis

Open access