Can the Understory Affect the Hymenoptera Parasitoids in a Eucalyptus Plantation?

Abstract

The understory in forest plantations can increase richness and diversity of natural enemies due to greater plant species richness. The objective of this study was to test the hypothesis that the presence of the understory and climatic season in the region (wet or dry) can increase the richness and abundance of Hymenoptera parasitoids in Eucalyptus plantations, in the municipality of Belo Oriente, Minas Gerais State, Brazil. In each eucalyptus cultivation (five areas of cultivation) ten Malaise traps were installed, five with the understory and five without it. A total of 9,639 individuals from 30 families of the Hymenoptera parasitoids were collected, with Mymaridae, Scelionidae, Encyrtidae and Braconidae being the most collected ones with 4,934, 1,212, 619 and 612 individuals, respectively. The eucalyptus stands with and without the understory showed percentage of individuals 45.65% and 54.35% collected, respectively. The understory did not represent a positive effect on the overall abundance of the individuals Hymenoptera in the E. grandis stands, but rather exerted a positive effect on the specific families of the parasitoids of this order.

Ecological importance of lepidopteran defoliators on eucalyptus plantations based in faunistic and natural enemy analyses

“…The total of 44 lepidopteran species, with 20 dominant and 24 non-dominants, is high and may be due to abundant ones, such as those from Noctuidae (Bernardi et al, 2011;Ribeiro et al, 2016). Some dominant insects can adapt to new environments by consuming the foliage of Eucalyptus and of alternative plants from the surrounding vegetation reducing the food available for other insect species (Bernardi et al, 2011;Dall'Oglio et al, 2016;Ribeiro et al, 2016). High populations of dominant insects in E. saligna and E. urophylla plantations with abundant food availability and the upgrade of new lepidopteran species to pest status indicate that competition for food resources between insects can occur in plantations with several eucalypt species (Zanuncio et al, 1998;Bernardi et al, 2008).…”

“…The number of defoliating Lepidoptera was lower in Eucalyptus cloeziana F. Muell., E. grandis and E. urophylla plantations, interspersed with strips of native vegetation, due to greater plant species diversity, favoring the reproduction of natural enemies and increasing biological control (Dall'Oglio et al, 2016;Zanuncio et al, 1998Zanuncio et al, , 2018.…”

“…Climatic factors, food availability and intra and interspecific competitions can also affect the activity, abundance, diversity and survival of these predators (Tavares, 2017). The forest fragmentation reduces the diversity and numbers of natural enemies, favoring outbreaks of pests and increasing the importance of community ecology studies (Bernardi et al, 2011;Dall'Oglio et al, 2016;Ribeiro et al, 2016).…”

First record in Brazil ofBrachymeria annulata(Fabricius) (Hymenoptera: Chalcididae) andTrichospilus diatraeaeCherian and Margabandhu (Hymenoptera: Eulophidae) parasitising pupae ofIridopsis panoplaProut (Lepidoptera: Geometridae) in eucalyptus (Myrtaceae)

“…This allows us to evidence that B. annulata and T. diatraeae are one of the biotic factors of natural pupae mortality. Therefore, conservation strategies for these parasitoids among the understorey and fragments of native vegetation surrounding the plantations are important for the population balance of eucalyptus lepidopterans defoliators (Dall'Oglio et al 2016). The Canadian Entomologist…”