A trade-off is a relationship between two life history characteristics principally reproduction and adult longevity that are fundamental in predicting the optimal life history in any given environment. Mating is indispensable for sexual reproduction, but also can impose risks to females. Nevertheless, in the majority of insects, females allow multiple mating. Dichelops furcatus (Hemiptera: Pentatomidae) is a pest of wheat and corn in Argentina and southern Brazil, but little is known about its reproduction (i.e., the characteristics of the process that results in offspring). We analyzed reproductive attributes of D. furcatus, and the effect of single mating vs. multiple matings, evaluating the trade-off between fecundity and adult female longevity. We found that mating is not required for D. furcatus to oviposit, and multiple copulations were costly in terms of reduced longevity. Although multicopulated females lived a shorter period, only the pre- and post-reproductive periods were shortened. Fecundity was not affected but fertility was incremented in multicopulated females. Females copulated only once oviposited most of the eggs in the first half of the reproductive period, while eggs oviposited in the second half were all inviable (did not hatch). Studying demographic attributes of phytophagous insects provides relevant information to better understand the population dynamics of pests.

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Actinostachys is a genus of the Schizaeaceae with two species reported from America: A. pennula and A. subtrijuga. The spores of the two species are studied using light microscopy, scanning electron microscopy and transmission electron microscopy. The spores are monolete, the equatorial diameter is 46-84 mm and the polar diameter is 26-50 mm. In A. pennula the ornamentation of the spores is foveolate and in A. subtrijuga it is striate, composed by parallel ridges separated by ornamented grooves. In both species, the exospore is two-layered and it is the wall that constitutes the ornamentation of the spores. The perispore is two-layered and thin with granules, and covers the outer surfaces of the exospore including the foveolae. On the spore surface of both species, abundant spheroids are observed. The ultrastructural analysis reveals that some of them are spherules and others globules. The studied species can be easily identified by their spores analysed with light microscopy even without prior treatment. We recommend that the spore ornamentation be included in dichotomous keys and descriptions of Actinostachys. The sporoderm ultrastructure of the species is described for the first time. The results contribute to the identification of the species and also may be valuable characters for systematic and phylogenetic purposes.

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