Where and when? How phenological patterns of armyworm moths (Lepidoptera: Noctuidae) change along a latitudinal gradient in Brazil

Abstract

The phenological patterns exhibited by different organisms are known as adaptive responses to the cyclical environmental conditions. However, only a limited number of researches explore which factors are responsible for these phenological patterns in pest species. In the current study, abundance patterns were studied in the phenology of three Spodoptera Guenée, 1852 species, along the 29° latitudinal gradient in South America. The goal was to test whether widely distributed and abundant crop pest species would exhibit different phenological responses to seasonal meteorological variables and host plant availability. To test this, 13 light traps were set up in Brazil to collect adult Spodoptera samples at the time of the new moon, every month, from June 2015 to May 2016. The time of occurrence and intensity of the phenology were determined for each species, employing circular statistics. Both metrics revealed significant variations among the different species, as well as the factors associated with them. Latitude was found to affect the period of occurrence in Spodoptera cosmioides (Walker, 1858) and Spodoptera albula (Walker, 1857), whereas in Spodoptera frugiperda (J. E. Smith, 1797) its effect was evident only in the intensity of its phenology. Further, both meteorological variables and host plant availability in the sampling sites produced predictive models to account for the phenological patterns expressed. These findings suggest that different species of Spodoptera exhibit different adaptive strategies in their life cycles in response to environmental conditions, thus necessitating specific management practices regarding their seasonal population fluctuation.

Variación temporal de la abundancia de mosquitos (Diptera: Culicidae) en el Bosque Atlántico subtropical de Brasil

“…In this way, to access these kinds of information we can use circular and linear statistical analyses. These analyses have already been used, for example, to verify and compare seasonal patterns between different forest fragments (Morellato et al 2000), to access the phenology of groups of specialist butterflies (Brito et al 2014) and to evaluate phenological patterns and the biotic and abiotic factors related to them through space and time on moth pest species (Piovesan et al 2018(Piovesan et al , 2019.…”

“…This test indicates the significance of the mean vector (µ), and the length of mean vector (r) determines if the observations are concentrated (H1) or uniformly distributed (H0). When the mean angle is significant, we reject the null hypothesis (Morellato et al 2000;Brito et al 2014;Piovesan et al 2018Piovesan et al , 2019. After rejecting the hypothesis of uniform yearly abundances, the mean vector (µ) can be used to represent the concentration of abundances for a specified period of the year.…”

Intercropped Bt and non‐Bt corn with ruzigrass (Urochloa ruziziensis) as a tool to resistance management of Spodoptera frugiperda (JE Smith, 1797) (Lepidoptera: Noctuidae)

“…However, the intensity of its occurrence is directly influenced by environmental factors, such as temperature and rainfall. 45,46 Although these environmental factors have not been considered in our study, the largest population was seen in the summer seasons (2018/2019 and 2017/2018), when the highest temperatures and rainfall occur in Brazil.…”

Spatio-temporal variation of Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) populations in Brazil according to meteorological factors

“…Spodoptera frugiperda is a polyphagous species (Montezano et al 2018) with high biotic potential (Montezano et al 2019a(Montezano et al , 2019b and, as in this study ( Table 2, fig. 1) it was collected in all the locations presented here (Piovesan et al 2018). It is important that M. latipes and other owlet moths, including S. frugiperda share the same predators, pathogens, also egg, larvae and pupae parasitoids (Silva et al 1968, Rogers & Marti Jr. 1993, Camera et al 2010.…”

“…Collections were made once a month, from July 2015 to June 2016, during each novilunium repeated for five nights (repetitions). Collection methodology followed Specht et al (2005) and Piovesan et al (2018). Traps were placed in areas surrounded by several agricultural crops, especially cotton, soybean, corn and pastures (Table 1).…”