External morphology of immature of Tynacantha marginata Dallas, 1851 (Hemiptera, Heteroptera, Pentatomidae)

Abstract

Immature stages of Neotropical Asopinae have been poorly studied. Here, the external morphology of eggs and nymphs of Tynacantha marginata Dallas are described using light and scanning electron microscopy. The egg is barrel-shaped with smooth surface, and long aero-micropylar processes. In the first instar, the color of abdomen varies along the development from yellow to red, the dorsal plates are pale, and the surface of evaporatorium bears spiked projections. From the second, the evaporatorium surface is reticulated. From third instar, the pronotum is orange with black lateral margins. The eggs and nymphs of T. marginata are unique among Neotropical Asopinae species of which the morphology is known, allowing the early identification of the species.

Morphology of Immature Stages, Chromatic Polymorphism of Adults and Natural History of Oplomus catena (Heteroptera: Pentatomidae: Asopinae)

“…First instar nymphs of Asopinae generally show similar characteristics: red abdomen and black to dark brown head and thorax (Grazia et al 1985, Brugnera & Grazia 2018, this study) which makes their identification difficult. From the second instar on, the nymphs show more evident differences between the species that allow distinguishing them.…”

“…The description of color patterns was carried out in vivo. Measurements are presented in millimeters (mean ± standard deviation [maximumminimum]) and were obtained according to Brugnera & Grazia (2018) (Table 1). Voucher specimens were deposited at the Entomological Collection of the Department of Zoology, Federal University of Rio Grande do Sul (UFRG).…”

“…Only about 1% of the immature stages of predatory stink bugs that occur in the neotropics have been studied so far. This lack of knowledge makes it difficult the identification of most of immature stages collected and prevents to include immature characters in taxonomic diagnosis and phylogenetic analysis (Matesco et al 2014, Brugnera & Grazia 2018.…”

“…Besides the underexplored morphology of Asopinae eggs, some studies show their remarkable diversity in size, shape, chorion sculpture, and size of aeromicropylar processes. Eggs of predatory stink bugs are known by the aero-micropylar processes, generally m u c h l o n g e r t h a n i n o t h e r s u b f a m i l i e s o f Pentatomidae (De Clercq 2000, Matesco et al 2009, as observed in Podisus Herrich-Schäffer, 1851 (Oetting & Yonke 1971, Grazia et al 1985, De Sá et al 2013, Brontocoris Thomas 1992, Supputius Distant, 1889(Dimaté et al 2014, Tynacantha Dallas, 1851 (Brugnera & Grazia 2018), Conquistator Gapon, 1992(Costello et al 2002, Troilus Stål, 1867 (Hinton 1981) among others. However, as Oplomus and Stiretrus, many genera exhibit short aero-micropylar processes, as Euthyrhynchus Dallas, 1851 , Alcaeorrhynchus Bergroth, 1891 , Picromerus Amyot & Serville, 1841, and Pinthaeus Stål, 1867 (Rieger 2000) These egg patterns observed among Asopinae genera seems to be correlated with their phylogenetic relationship, which can be useful for the systematics of the group and should be more investigated..…”

“…The use of alternative methods to control pests in crops is increasingly important to reduce the use of pesticides and keep a balance between agricultural and ecological systems. However, the biology and morphology of immature stages of these predators are poorly studied which makes their application in biological control and pest management programs difficult (Cohen 2000, Schaefer & Panizzi 2000, Brugnera & Grazia 2018.…”