Morphological description of the third instar larva ofLasiotrichius succinctus hananoi(Sawada) (Coleoptera: Scarabaeidae: Cetoniinae: Trichiini), using scanning electron microscopy

Abstract

Cetoniinae is one of the showiest scarab groups, exhibiting bright‐metallic body colors, and usually attract great attention from entomologists and amateur collectors. Larvae of Cetoniinae show dramatically diversity on morphology and living habits. Although being considered one of the best‐studied groups of Scarabaeidae, larvae have been described for less than 5% species to the known Cetoniinae. In this study, the final instar larva of Lasiotrichius succinctus hananoi was described using scanning electron microscopy. The larvae are peculiar for bearing a haptomeral process dividing 10 spines into two groups: six on the left side, four on the right side, different from the previous descriptions on L. succinctus (Pallas, 1781). The morphological differences under SEM imply the further requirement of taxonomic revision in Lasiotrichius. Both advantage and disadvantage of SEM utilizing in larval descriptions were briefly discussed.

Morphology of a grass‐feeding white grub Apogonia cupreoviridis (Coleoptera: Scarabaeidae: Melolonthinae: Diplotaxini) using scanning electron microscopy

“…The sensilla on antennal apex are quite diverse among white grubs in Scarabaeoidea, although they are rarely mentioned in the previous studies without electron microscopy (Ritcher, 1966; Sawada, 1991; Zhang, 1984). The larvae usually possess seven short sensilla basiconica in Cetoniinae (Dong et al, 2020), eight sensilla basiconica in some Rutelinae (Fang et al, 2018); five short sensilla basiconica and a long sensillum trichodeum in some Aphodiinae (Li et al, 2019); and none in Prismognathus dauricus (Lucanidae) (Qu et al, 2019). In Melolonthinae, the larval antennae have 11 sensilla basiconica in Melolontha melolontha (Eilers et al, 2012) and M. incana (Jia et al, 2021), 21 sensilla basiconica in Pseudosymmachia tumidifrons , and 26 in Brahmina faldermanni (Jia et al, 2020).…”

“…Larvae of Melolonthinae, similar to others in Scarabaeoidea, are generally C‐shaped and called white grubs (Capinera, 2008), which exhibit dramatic diversity on feeding habits. The white grubs are saproxylic and feeding on decayed woods in Lucanidae (Qu et al, 2019), consuming sawdust in some Cetoniinae, Dynastinae and Euchirinae (Dong et al, 2020; Šípek et al, 2011; Šípek & Král, 2012; Sousa et al, 2018; Vondráček et al, 2018), being coprophagous in some Aphodiinae and Scarabaeinae (Li et al, 2019), and attacking plant organs in some “pest taxa,” including Rutelinae and Melolonthinae (Jia et al, 2020, 2021). Accurate species identification is a necessary prerequisite for determining the feeding habits of white grubs, and making decides whether, when and how to control them (Frew et al, 2016; Johnson et al, 2016; Ritcher, 1966).…”

Morphological description of the white grub Melolontha incana (Coleoptera: Scarabaeidae: Melolonthinae: Melolonthini)

“…In Melolonthini, the number of heli are more than 30 in Lepidiota acuminata Moser, 1913 (Zhang, 1984), no more than 20 in Polyphylla arguta Casey, 1914 (Hayes, 1928), 12 in M. melolontha (Böving, 1942), and 14 in M. incana . On the contrary, the number of heli are less than five in Rutelinae (Fang, Li, & Jiang, 2018), and even absent in Cetoniinae, Dynastinae, Aphodiinae, and Scarabaeinae (Dong, Jia, & Jiang, 2020; Li, Lu, Fang, & Jiang, 2019; Ritcher, 1966; Sousa, Fuhrmann, Kouklík, & Šípek, 2018).…”

“…Similar setae were also observed in other multivoltine species such as M. japonica Burmeister, 1855 (Sawada, 1991) and Polyphylla laticollis Lewis, 1887 (Zhang, 1984). On the contrary, these setae are sparse and slim in the other univoltine species Brahmina faldermanni and Pseudosymmachia tumidifrons in Melolonthinae (Jia, Lu, Zhou, & Jiang, 2020), the univoltine species Adoretus tenuimaculatus in Rutelinae (Fang et al, 2018), and other non‐phytophagous species in Cetoniinae, Aphodiinae and Lucanidae (Dong et al, 2020; Li et al, 2019; Qu et al, 2019; Sousa et al, 2018). Although these setae were not clearly mentioned in most of the previous studies in Melolonthinae (Aragón & Morón, 2000, 2004; Hernández‐Cruz et al, 2016), these structures were named as fossorial setae by Ritcher (1966), and believed to provide more locomotive abilities during their longer larval stage.…”