Morphological and morphometric analysis of scutella of six species and two subspecies of Triatoma (Hemiptera: Reduviidae) in Mexico.

Morphological characters can be used to distinguish the vast majority of triatomine species, but the existence of high levels of phenotypic plasticity and recently diverged species can lead to erroneous determinations. To approach this problem, we analyzed the male and female morphologies of the scutella of Triatoma barberi, T. dimidiata, T. lecticularia, T. mexicana, T. recurva, T. rubida, and two sub-species, T. protracta protracta and T. protracta nahuatlae. Scutellum samples were observed by scanning electron microscopy and subjected to morphological analysis and morphometric investigation using a canonical discriminant analysis. The results revealed differences primarily in central depression shape, posterior process, and vestiture. We observed clear dimension-based differences in scutellum morphometry in all the taxa under study, providing sound evidence for species and subspecies differentiation. On the other hand, there is no difference between sexes in T. lecticularia, T. protracta protracta, and T. protracta nahuatlae. Our methodology can be implemented to differentiate species of the genus Triatoma.

Effect of photoperiod on characteristics of semen obtained by electroejaculation in stump-tailed macaques (Macaca arctoides).

Some environmental variables determining seasonal reproduction in mammals are temperature, humidity, food availability, and photoperiod. Among these, photoperiod is considered the main regulator of primates' seasonal reproduction, thus the latitudinal distribution of primate populations is a key factor determining the appearance of seasonal reproduction. The present work presents supporting discrete seasonality in male stump-tailed macaques (Macaca arctoides). We investigated whether semen quality and testosterone covaried with Mexico City's photoperiod and relative humidity by analyzing variations in the portions that form the ejaculate: the seminal liquid, the seminal coagulum, and the copulatory plug. Five male adult stump-tailed macaques were electroejaculated once a month, obtaining three semen samples per male, from August 2011 to July 2012 (except for December 2011) (n = 165). Our results showed that stump-tailed macaque sperm counts were significantly different between the portions of the ejaculate. The seminal coagulum contained the significantly largest number of spermatozoids, followed by the copulatory plug and the seminal fluid. Photoperiod and relative humidity had major influence on the sperm count in the seminal coagulum and the testosterone concentrations. Testosterone reached its highest values around the time when days and nights lasted the same hours, decreasing when days either grew longer or became shorter. Concerning relative humidity, sperm counts in the seminal coagulum were highly variable on dry days, but decreased as the relative humidity increased. We conclude that stump-tailed macaques have a discrete seasonality, occurring in spring and fall when macaques' reproductive condition and readiness for postcopulatory intrasexual competition increase.

Evolution and ecology of Calopterygidae (Zygoptera: Odonata): status of knowledge and research perspectives

We review the studies of evolution and ecology in the Calopterygidae. Adults are easily distinguished for their pigmented wings and territorial behaviour. Three genera have been well studied: Hetaerina, Calopteryx and Mnais. Larvae develop in riverine aquatic environments. Selection operates at this stage to produce large muscle mass for adults. The adult spends some days until sexually ready. During this time, it feeds extensively to produce muscle fat for egg production and flight. However, gregarine parasites may ingest the fat reserves. Males may use two mating tactics or strategies that may be genetically (Mnais) or environmentally (Calopteryx and Hetaerina) determined: territoriality and nonterritoriality. In Mnais, these strategies appear balanced in fitness terms. Males of Calopteryx, Mnais and Phaon show a precopulatory courtship that is not the case for Hetaerina. Male wing pigmentation seems to signal how good the male is to deal immunologically with parasites to females during the male courtship. During copulation, males displace the sperm the female has stored in the storage organs from previous matings. There is an enormous variation in male sperm displacement mechanisms and ability, and in genitalic morphology in both sexes. This variation possibly results from a coevolutionary game between the sexes to control stored sperm. After copulation, males guard females apparently to avoid that other males take the female in copulation. Our review suggests sources for research in this family.

Neste artigo revisamos estudos sobre evolução e ecologia da família Calopterygidae. Os adultos são reconhecidos pelas asas pigmentadas e comportamento territorial. Três gêneros têm sido bem estudados: Hetaerina, Calopteryx e Mnais. As larvas desenvolvem-se em ambientes aquáticos e a seleção opera principalmente nesse período, resultando em indivíduos de grande massa muscular. Os adultos levam alguns dias para se tornarem sexualmente maduros e durante esse período alimentam-se extensivamente acumulando as reservas de gordura que consumirão para voar e produzir ovos. Entretanto, gregarinas parasitas podem consumim essas reservas. Os machos utilizam duas estratégias de acasalamento que podem ser determinadas geneticamente (Mnais) ou ambientalmente (Calopteryx e Hetaerina): territorialidade e não-territorialidade. No gênero Mnais as estratégias comportamentais parecem ser balanceadas de acordo com sua adaptabilidade ao longo do tempo. Os machos de Calopteryx, Mnais e Phaon realizam corte pré-cópula, comportamento ausente em Hetaerina. A pigmentação das asas dos machos parece sinalizar às fêmeas, durante a corte, algum nível de resistência imunológica a parasitas. Durante a cópula os machos retiram o esperma armazenado em cópulas anteriores pelas fêmeas. Há grande variação na habilidade e nos tipos de mecanismos para a retirada do esperma, assim como na morfologia genital de ambos sexos. Tal variação pode resultar de co-evolução entre os sexos direcionada a controlar o esperma armazenado. Após a cópula os machos defendem as fêmeas evitando que elas copulem com outros machos. Nessa revisão sugerimos aspectos a serem estudados nessa família.