The structure and morphogenic changes of antennae of Matsucoccus matsumurae (Hemiptera: Coccoidea: Matsucoccidae) in different instars

•The antennae display three different styles in three different instars.•The first instar antenna is simple and possesses chemoreceptors mainly.•The third instar antenna is more developed and possesses more mechanoreceptors.•The adult male antenna is the most developed and possesses massive chemoreceptors.•The antennal development in the pupa-like stage is different from that of holometabolous pupae.

To better understand the functioning and morphogenic changes of the antennae of Matsucoccus matsumurae (Kuwana) in different instars, the antennae are examined using light microscopy, scanning and transmission electron microscopy. The results show that the antennae of M. matsumurae display three different styles in morphology and sensillar distribution in different instars. The antennae of first instar nymphs are relatively simple, including one campaniform sensillum (Ca), four smooth aporous trichoid sensilla (SAt), two intersegmental sensilla (Ins), two coeloconic sensilla (Co), three multiporous pegs (Mp) and four uniporous pegs (Up). The antennae of adult females and third instar male nymphs both possess similar antennae, and exhibit seven types of sensilla. Adult female antennae have in total 82–108 sensilla, including 9–16 Böhm's bristle (Bb), 3–7 Ca, 50–75 SAt, 0–3 Ins, 3–10 Co, 8 Mp and 5 Up, whereas third instar male nymph antennae possess approximately 62–79 sensilla. Adult male antennae are the most developed, possessing 259–312 sensilla, including 7–15 Bb, 2–5 Ca, 7–11 grooved aporous trichoid sensilla, 4–9 SAt, 0–3 Ins, 2–7 Co, 23–29 knobbed seta sensilla, 179–230 multiporous trichoid sensilla and 8 Mp. Based on these results, the main functions and morphogenic changes of antennae M. matsumurae in different instars are discussed.