Field distribution patterns of pests are asymmetrically affected by the presence of other herbivores.

Because plant phenotypes can change in response to attacks by herbivores in highly variable ways, the distribution of herbivores depends on the occurrence of other herbivore species on the same plant. We carried out a field study to evaluate the co-occurrence of three coconut pests, the mites Aceria guerreronis (Acari: Eriophyidae), Steneotarsonemus concavuscutum (Acari: Tarsonemidae) and the moth Atheloca bondari (Lepidoptera: Pyralidae). The eriophyid mite Ac. guerreronis is the most important coconut pest around the world, whereas S. concavuscutum and At. bondari are economically important only in some areas along the Brazilian coast. A previous study suggested that the necrosis caused by Ac. guerreronis facilitates the infestation of At. bondari larvae. Because all three species infest the area under the perianths on coconuts and S. concavuscutum also causes necrosis that could facilitate At. bondari, we evaluated the co-occurrence of all three species. We found that the occurrence of At. bondari was positively associated with Ac. guerreronis, but negatively associated with S. concavuscutum. In addition, the two mite species showed negative co-occurrence. Atheloca bondari was found on nuts of all ages, but more on nuts that had fallen than on those on the trees, suggesting that nuts infested by At. bondari tend to fall more frequently. We discuss the status of At. bondari as a pest and discuss experiments to test the causes of these co-occurrence patterns.

Which Species of Coconut Moth Occurs in Brazil: Atheloca subrufella vs. Atheloca bondari (Lepidoptera: Pyralidae)?

The moths, Atheloca subrufella (Hulst 1887) and A. bondari, (Heinrich 1956) are species known for their economic impact on coconut production, which Brazil is the fourth largest global producer. The first record of Atheloca in Brazil was reported by Bondar in 1940, where the author registered it being A. subrufella. The studies performed by C. Heinrich in 1956 related the existence of divergence in specimens of Brazilian Atheloca suggesting the presence of morphological differences between the males of A. bondari and A. subrufella. In this study, Atheloca specimens from the five states of northeastern Brazil were used. Samples from Pernambuco state were sent to taxonomist Dr. V. O. Becker (Uiraçu Institute-BA) for identification. Male individuals from the other states were mounted for photographic documentation, highlighting the characteristics that differentiate the two species. A fragment of the cytochrome c oxidase subunit 1 gene was sequenced and then compared with that of the Atheloca spp. deposited in GenBank. An analysis was conducted to evaluate the genetic distance between A. bondari and A. subrufella. The results indicate greater interspecific (0.030-0.034) than intraspecific (0.000-0.002) genetic variation between the groups, reinforcing the hypothesis of two distinct species. A geographic distribution map and a table with the host plants were constructed based on a literature review. This study concluded that the species occurring in Brazil is A. bondari, as suggested by C. Heinrich. Atheloca bondari and A. subrufella have only been reported in plants of the family Arecaceae, but only the coconut tree (Cocos nucifera L.) is shared by the two species.

Acaricide activity in vitro of Acmella oleracea against Rhipicephalus microplus.

Cattle tick control has been limited by the resistance of these parasites to synthetic acaricides. Natural products are a possible alternative as they have different mechanisms of action. Acmella oleracea is a native plant with a large cultivated area in the Amazon region and could be easily used for large-scale preparation of a commercial product. This study evaluated the in vitro action of the hexane extract of the aerial parts of A. oleracea on larvae and engorged females of the cattle tick Rhipicephalus microplus. Spilanthol was the major constituent with a content of 14.8% in the extract. The hexane extract of A. oleracea was highly effective against larvae of R. microplus with an LC50 of 0.8 mg mL(-1). Against engorged females, hexane extract of A. oleracea reduced oviposition and hatchability of eggs with an LC50 of 79.7 mg mL(-1). Larvae and engorged females were killed by the hexane extract with high efficiency (>95%) at concentrations of 3.1 and 150.0 mg mL(-1), respectively. These results demonstrate that the hexane extract of A. oleracea has significant activity against R. microplus and has potential to be developed into formulations for tick control.