Zoological Studies

Vol. 59, 2020

(update: 2020.03.10; 04.10)

Roosting Site Usage, Gregarious Roosting and Behavioral Interactions During Roost-assembly of Two Lycaenidae Butterflies

Yuan-Mou Chang1,*, Kent A. Hatch2, Mei-Yi Ho1, Stephen H. Roxburgh3, Yi-Ting Wu1, Yi-Kuang Wang1, Shuang-Ru Wang1, and Zi-Xuan You1


1Department of Ecology and Environmental Resources, National University of Tainan, 33 Su-Lin Street, Section 2, Tainan 700, Taiwan. *Correspondence: E-mail: changyuanmou@gmail.com (Chang)
  E-mail: meiyiher@gmail.com (Ho); ejleci@hotmail.com (Wu); ykwang@mail.nutn.edu.tw (YK Wang); v.w.sagittarius@gmail.com (SR Wang); ann870321@gmail.com (You)
2Department of Biology, Long Island University – Post, Brookville, NY, USA. E-mail: kent.hatch@liu.edu (Hatch)
3CSIRO Land & Water, GPO Box 1700, Canberra ACT 2601 / Clunies Ross Street Acton ACT 2601. E-mail: stephen.roxburgh@csiro.au (Roxburgh)

Received 15 July 2019 / Accepted 9 March 2020
Communicated by Shen-Horn Yen

Lycaenidae is one of the larger of the world’s butterfly families, based on number and diversity of species, but knowledge of roosting in this group is sparse. Zizina otis riukuensis and Zizeeria maha okinawana are two small lycaenids that are commonly found in urban settings and widely distributed across much of Asia. We conducted experiments on a university campus to determine the plant species and plant structures
commonly used by these two blues when roosting. We also tested the hypothesis that gregarious roosting exists in these two blues by demonstrating the non-random distribution of roosting blues and the tight mapping of their roosts to the spatial distribution of specific plant species and/or specific plant structures, as well as by demonstrating behavioral interactions among individuals during roosting-assembly. We found that both Z. otis and Z. maha roosted primarily on flowers and fruits of Tridax procumbens and Vernonia cinerea. We also found that these blues formed conspicuous roosting aggregations with significant positive associations between the flowers and fruits of both T. procumbens and V. cinerea and the blues. Moreover, our behavioral observations showed that these blues expressed various levels of interaction during roosting gatherings. Based on these findings, we conclude that gregarious roosting exists in both Z. otis and Z. maha. To our knowledge, this paper represents one of the first demonstration of nocturnal gregarious roosting in lycaenids. This study also highlights the importance of institutional estates in providing roosting resources for butterflies in urban ecosystems.

Key words: Nocturnal roosting, Zizina otis riukuensis, Zizeeria maha, Roosting aggregation, Lycaenidae, Institutional estates, Conservation biology.

Citation: Chang YM, Hatch KA, Ho MY, Roxburgh SH, Wu YT, Wang YK, Wang SR, You ZX. 2020. Roosting site usage, gregarious roosting and behavioral interactions during roost-assembly of two Lycaenidae butterflies. Zool Stud 59:10. doi:10.6620/ZS.2020.59-10.