ABSTRACT Studies that address biodiversity and its supporting mechanisms in different ecosystems are fundamental to understanding the relationships between species and the prevailing environmental conditions within each habitat type. This study presents information on the phenology of Promestosoma boggianii (Silvestri, 1898) and its association with seasonal flood and dry events in a floodplain of Mato Grosso’s northern Pantanal region, Brazil. Sampling was carried out in three areas located between the Bento Gomes and Cuiabá rivers, on the Porto Cercado Road, Poconé-MT. Each sample area was composed of two treatments: (I) floodable habitats and (NI) non-floodable habitats. Three quadrats (10 x 10 m) were established within each treatment, with sampling carried out using pitfall traps and mini-Winkler extractors during the dry season, rising water, high water and receding water phases for the duration of two hydrological cycles within the Pantanal (2010/2011 and 2011/2012). A total of 295 P. boggianii individuals were sampled at different stages of development (except stages I and II), distributed between the rising water (209 ind., 70.8%), dry (76 ind., 25.8%) and receding water (10 ind., 3.4%) seasons. No specimens were sampled during the high water season. The higher abundances recorded between the dry and rising water seasons, primarily at early stages of development, indicate that P. boggianii is characterized as a univoltine species in these habitats. The data demonstrate that individuals of P. boggianii were more abundant in floodable habitats. In addition, the results show that the life cycle of this diplopod is sinchronized to the seasonal nature of this floodable environment, as a strategy to survive the extreme conditions of terrestrial and aquatic phases Brazil’s northern Pantanal region.

Cornops aquaticum (Bruner) has Eichhornia crassipes, E. azurea, Pontederia cordata and P. lanceolata (Pontederiaceae) as the known host plants. This grasshopper species is cited as a possible agent of biological control for native aquatic macrophytes E. azurea and E. crassipes. This study, carried out from March, 2006 to February, 2007, aimed to evaluate the phenology and age structure of the population of C. aquaticum associated with E. azurea in Piuval bay, Pantanal of Poconé, MT, and to identify possible relationships of its life cycle to abiotic factors such as insolation, temperature and precipitation. Monthly collections of 50 individuals were carried out according to the protocol defined by the "Host - Insect Coevolution on Waterhyacinth" project. Adults and nymphs were separated and the females dissected in order to evaluate ovary maturation. The population presented adults and nymphs during the whole year, suggesting the occurrence of more than one reproductive period. The nymphs from the first stage predominated in August 2006 and the adults in September and October 2006, synchronized with the dry period and beginning of the flooding period, respectively. The highest relative abundance of the females with mature ovaries occurred in July 2006 (50%), indicating that this may be a more propitious period for reproduction. The data suggest that C. aquaticum is a species in continual reproduction in Piuval bay and its cycle is associated with the environmental conditions guided by the flood pulse in the Pantanal of Mato Grosso.

Even though millipedes display high plasticity in their reproductive strategies, they are poorly studied in the tropical region. The present study describes the biological cycle and reports the parthenogenetic reproduction of Poratia salvator Golovatch & Sierwald, 2000 under environmental conditions. Collections were carried out in Pantanal of Mato Grosso and in Várzea Grande, state of Mato Grosso, Brazil. The individuals were kept at room temperature in individual plastic pots. All 18 females used in the experiment reproduced parthenogenetically, resulting in a total of 699 young individuals. Of these, 18% survived until the adult phase. The lowest survival rate of P. salvator was recorded for the first developmental stage (46%). The mean duration of each developmental stage ranged between 6.8 ± 0.8 days for stage I and 14.9 ± 10.4 days for stage VI. The reproductive adult phase of females was the longest phase in the development, followed by the juvenile and pre-reproductive adult phases. The mean time of maturity was 75.1 ± 23.6 days. The mean duration of the total development was 66.1 ± 16.7 days. The number of eggs per nest varied between seven and ten, and the emergence of young individuals occurred after an average of 9.9 ± 1.4 days. Sexual proportion was 1 male:139.8 females, which indicates a tendency towards a parthenogenetic reproduction in this species.