Biology, Behavior, and Larval Morphology of Salbia lotanalis (Lepidoptera: Crambidae), a Potential Biological Control Agent of Miconia calvescens (Myrtales: Melastomataceae) from Costa Rica

Abstract

The leaf roller Salbia lotanalis Druce (Lepidoptera: Crambidae), a potential biological control agent of Miconia calvescens de Candolle (Melastomataceae), was studied in Costa Rica. Larvae were collected from a field site near San José and the insect was reared in the laboratory to study its biology and behavior. Chaetotaxy and morphology of final-instar larvae were described. Using head capsule width measurements, we determined five larval instars in S. lotanalis. The insect was easily reared in the laboratory on M. calvescens seedlings and the life cycle of the insect was completed in 71.3 and 66.4 d for females and males, respectively. Dissection of ovarioles indicated that females could lay>400 eggs. Larvae are initially gregarious, but become solitary as third instars. First- to fourth-instar larvae prefer to use leaf rolls already formed by other larvae, but fifth-instar larvae prefer to make a new leaf roll rather than using leaf rolls already made and occupied by other larvae. Pupation occurs in leaves, where prepupae build a pupation chamber. Host-specificity tests, including larval feeding tests and two-choice and no-choice oviposition experiments in the laboratory, indicate that S. lotanalis has a narrow host range restricted to Miconia spp. and other Melastomaceae. Levels of parasitism in the native habitat of S. lotanalis in Costa Rica were low. In locations like Hawaii, where there are no native Melastomataceae, S. lotanalis has the potential of being an effective biological control agent against M. calvescens, but interference from resident natural enemies of Lepidoptera could be high.

Damage toMiconia calvescensand Seasonal Abundance ofSalbia lotanalis(Lepidoptera: Crambidae) in Costa Rica

“…By the end of the dry season in March 2007, trees had lost half their leaves compared with the previous November. Feeding by S. lotanalis larvae can make M. calvescens leaves fall off (Castillo 2009, Morais et al 2010, Castillo et al 2014; however, some loss of foliage is typical for M. calvescens during the relatively severe dry season in San José Province (Johnson, unpublished data). Thus, seasonal drought probably explains the decline of S. lotanalis densities observed in this study.…”

“…lotanalis are easy to rear in the laboratory, have a short life cycle and a high reproductive rate, and appear to be restricted to M. calvescens and other Melastomataceae (Castillo 2009, Janzen and Hallwachs 2009, Morais et al 2012, Castillo et al 2014, traits that appear to make it a suitable candidate for biological control. Feeding by S. lotanalis larvae has been shown to reduce growth of M. calvescens in greenhouse conditions (Morais et al 2010), and our results suggest that defoliation and leaf rolling by S. lotanalis larvae could substantially reduce leaf area and shade produced by M. calvescens.…”

“…However, efÞcacy of S. lotanalis against M. calvescens outside its native range will also depend on biotic factors affecting population growth. At our study site in Costa Rica, S. lotanalis larvae and pupae were rarely parasitized (Castillo 2009, Castillo et al 2014, and in Brazil parasitism was …”

“…A variety of neotropical arthropods and pathogens have been evaluated as potential biological control agents of M. calvescens in recent years, but so far only a fungal pathogen has been released in Hawaii and Tahiti (Killgore 2002, Picanç o et al 2005, Badenes-Perez et al 2008, Hanson et al 2010, Conant et al 2013). Among insects evaluated as potential agents, Salbia lotanalis Druce (Lepidoptera: Crambidae), whose larvae tie leaves producing large leaf rolls within which they feed, has been the subject of biology and hostspeciÞcity studies in Brazil (Morais et al 2010(Morais et al , 2012 and Costa Rica (Castillo 2009, Castillo et al 2014. The insect has Þve larval instars and completes one generation in 60 Ð90 d (Morais et al 2010, Castillo et al 2014.…”

“…Among insects evaluated as potential agents, Salbia lotanalis Druce (Lepidoptera: Crambidae), whose larvae tie leaves producing large leaf rolls within which they feed, has been the subject of biology and hostspeciÞcity studies in Brazil (Morais et al 2010(Morais et al , 2012 and Costa Rica (Castillo 2009, Castillo et al 2014. The insect has Þve larval instars and completes one generation in 60 Ð90 d (Morais et al 2010, Castillo et al 2014. Host-speciÞcity testing in Brazil showed that third-instar S. lotanalis feed and develop successfully on M. calvescens and Clidemia hirta (L.) D. Don (Melastomataceae), but not on other Melastomataceae (Morais et al 2012).…”