Cassidinae, Gyllenhal, 1813

Cassidinae View in CoL

Cassidinae Gyllenhal, 1813 View in CoL are a large subfamily containing 6,376 species classified in 358 genera and 33 tribes (Sekerka, unpubl. data). The species are distributed worldwide with greater diversity in the Neotropics ( Chaboo 2007, Borowiec and Świetojańska 2014, 2024). In general, Cassidinae View in CoL are better studied than any other chrysomelid group as the subfamily has always had specialists working on it continuously since the 1850’s. In the past, the group was considered as two separate subfamilies Cassidinae View in CoL (“tortoise beetles” – cassidiforms) and Hispinae View in CoL (“leaf-mining beetles” – hispidiforms) together forming the group Cryptostoma (e.g., Chapuis 1874, Crowson 1938, Monrós and Viana 1947). Already, early authors suggested similarity between the two subfamilies as some tribes were considered transitional, which generated several changes in their classification over the years (see Staines (2002) to a brief review of the classification history). However, since the first modern phylogenetic analyses of cassidines based on morphological data ( Borowiec 1995), many authors have been proposing the placement of the taxa under the subfamily Cassidinae View in CoL ( Reid 1995, Lawrence and Newton 1995, Suzuki 1996, Chaboo 2007, Gómez-Zurita et al. 2008, Bocak et al. 2013). Internal classification of Cassidinae View in CoL is quite stable and most tribes are supported by morphological data based on the larvae as well as adults ( Borowiec 1995, Chaboo 2007).

Compared to other chrysomelid subfamilies, Cassidinae View in CoL have much more diverse biology, life strategies, and larval and adult morphology known ( Chaboo 2007). The larvae can be fully exophagous, hidden in narrow crevices of their host plant (“cryptic”), or mining inside leaves ( Staines 2004, Chaboo 2007). There are two main trends, which can be observed: 1) early diverging hispidiform lineages are primarily associated with monocots, while cassidiforms are associated with eudicots; and 2) tribes with leaf mining larvae use many more plant families than those with exophagous larvae; Cassidiforms have eruciform larvae with caudal abdominal processes usually bearing exuvial or fecal shields, often combined, which are absent to most hispidiforms ( Sekerka 2017).

The diversity of Cassidinae is almost equally divided between New and Old World. The New World has 3,173 species in 17 tribes with only the tribe Cassidini being shared between the two regions. Brazil has the highest diversity in the world, with 1,477 species, 826 of which are known only from Brazil. However, the number of truly endemic species is likely much lower, as research in neighboring countries has been limited, and some species are also found in other countries, such as Bolivia (Sekerka, unpubl. data). Most Brazilian taxa have not undergone taxonomic revision since their original description; therefore, a decrease in the number of species can be expected due to synonymy. On the other hand, Brazil likely still has numerous undescribed species, as cassidines (particularly hispine tribes) have cryptic lifestyles and require specific collection methods on their host plants.

The most prolific Cassidinae authors were C. H. Boheman (508 spp. ~ 34%), Franz Spaeth (1863–1946) (184 spp. ~ 12%), J. Weise (127 spp. ~ 8.5%), Erich Uhmann (1881–1968) (112 spp. ~ 7.5%), J. S. Baly and M. Pic (each 110 spp. ~ 7.4%). Together these authors described 77.9% of Brazilian Cassidinae fauna. A large amount of information is summarized and available online, including key to the world genera and photo gallery (to ‘cassidines’ see Borowiec and Świetojańska (2024); to ‘hispines’ see Staines (2015)). Brazilian Cassidinae have been widely studied in terms of ecological and biological aspects since the 1980’s. Many species have been studied in terms of their natural history (e.g., Buzzi 1988, Nogueira-de-Sá and Trigo 2002, Nogueira-de-Sá and Vasconcellos-Neto 2003b, Flinte et al. 2009a, Chaboo et al. 2014, Albertoni and Casari 2017), immature stages (e.g., Świętojańska and Medeiros 2007, Fernandes and Buzzi 2007, Casari and Teixeira 2010), and host-plant association (e.g., Medeiros et al. 1996, Nogueira-de-Sá and Vasconcellos-Neto 2003a, Gomes et al. 2021).