University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Faculty Publications: Department of Entomology Entomology, Department of 2015 Developmental Biology and Effects of Adult Diet on Consumption, Longevity, and Fecundity of Colaspis crinicornis (Coleoptera: Chrysomelidae) Kentaro Miwa University of Nebraska-Lincoln Lance Meinke University of Nebraska--Lincoln, [email protected] Follow this and additional works at: http://digitalcommons.unl.edu/entomologyfacpub Part of the Entomology Commons Miwa, Kentaro and Meinke, Lance, "Developmental Biology and Effects of Adult Diet on Consumption, Longevity, and Fecundity of Colaspis crinicornis (Coleoptera: Chrysomelidae)" (2015). Faculty Publications: Department of Entomology. 412. http://digitalcommons.unl.edu/entomologyfacpub/412 This Article is brought to you for free and open access by the Entomology, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications: Department of Entomology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Journal of Insect Science RESEARCH Developmental Biology and Effects of Adult Diet on Consumption, Longevity, and Fecundity of Colaspis crinicornis (Coleoptera: Chrysomelidae) Kentaro Miwa and Lance J. Meinke1 Department of Entomology, University of Nebraska - Lincoln, Lincoln, NE 68583 1Corresponding author, e-mail: [email protected] Subject Editor: John Ewer J. Insect Sci. (2015) 15(1): 78; DOI: 10.1093/jisesa/iev062 ABSTRACT. The chrysomelid beetle Colaspis crinicornis Schaeffer (Coleoptera: Chrysomelidae) occurs primarily in the Great Plains region of the United States. Little is known about the biology and ecology of this species, but over the last decade, it has become in- creasingly common in the corn, Zea mays L., and soybean, Glycine max (L.) Merrill, agroecosystem of southeastern Nebraska. As part of a larger comprehensive project to understand the natural history and pest potential of this species, laboratory experiments were conducted to study the developmental biology, morphological characters of immature stages, and the effect of adult diet on consump- tion, longevity, and fecundity. Females readily deposited egg clusters in the soil, and percentage egg hatch was high under laboratory conditions. Larvae and pupae were confirmed to be soil-dwelling stages. C. crinicornis has relatively short egg, pupal, and adult stages with the majority of its life cycle spent in the larval stage. Results of choice and no-choice adult feeding experiments indicate that diets of corn or soybean leaves did not significantly affect consumption, longevity, or fecundity of adult C. crinicornis, suggesting that corn and soybean leaves are similarly suitable food sources for adults. The ability to effectively utilize tissues from very different plant fami- lies as adult food sources suggests that C. crinicornis is polyphagous in the field. Key Words: Chrysomelidae, Eumolpinae, Colaspis crinicornis, developmental biology The leaf beetle genus Colaspis (Coleoptera: Chrysomelidae) contains experiments conducted to quantify basic aspects of developmental biol- over 200 species and is the largest New World genus in the subfamily ogy, describe immature stages, and characterize the effect of adult diet Eumolpinae (Riley et al. 2002). Approximately 28 species are currently on consumption, longevity, and fecundity. recognized in the United States and Canada (Riley et al. 2002). Most of what is known about Colaspis biology and ecology has been obtained Materials and Methods from studies of the few species that can be agricultural pests (Lindsay Developmental Biology Experiments 1943, Echols 1963, Rolston and Rouse 1965, Ostmark 1975, Adult Collection. Live adult C. crinicornis were collected in corn- Balsbaugh 1982, Flynn and Reagan 1984, Oliver 1987, Lopez et al. fields in Nemaha County, NE, for all laboratory experiments using 2002). Adults generally feed on plant shoot systems, whereas soil- screen emergence cages based on a modified design of Fisher (1980). inhabiting larvae feed on below-ground portions of plants (Lindsay The inside of each cage was kept free of corn leaves and weeds to mini- 1943, Echols 1963, Ostmark 1975, Lopez et al. 2002). Some species mize feeding by newly emerged beetles. Beetles were recovered from are highly polyphagous, whereas others have more specific host ranges the cages every 3–4 d from inverted glass jars placed at the highest (Riley et al. 2002, Clark et al. 2004). point of the cage. This type of emergence cage was originally devel- Colaspis crinicornis Schaeffer is one of the larger species among oped to collect Diabrotica species in corn, but because of the similar the yellow-brown, costate Colaspis species found in the United States behavior exhibited by both Diabrotica and Colaspis species, involving (Fig. 1) and primarily occurs in the Great Plains (Blake 1974, Riley upward movement from the soil level after emergence, the cage worked et al. 2003). Museum specimens indicate that C. crinicornis records well to capture Colaspis beetles. Beetles were transported to the labora- from Nebraska date back to the 1910s, but its presence in crop fields tory in a cooler, and sex was determined for each beetle under a dissect- was not recorded in Nebraska or Iowa until the mid-1990s or early ing microscope based on descriptions given by Chapin (1979) before 2000s (Bradshaw et al. 2011, L.J.M., personal observation). Population placing them in oviposition containers on the days of collection. Only densities of C. crinicornis have been increasing during the last decade active individuals were used in the laboratory experiments, and no evi- (L.J.M., personal observation) to the point that the species can be abun- dence of adult infection by natural enemies such as nematodes or fungi dant in some locations (Miwa 2014). However, in contrast to some of was observed during the experiments. Identification of specimens col- the Colaspis species that have been associated with agricultural crops lected during this study was confirmed by E. G. Riley at Texas A&M for many years, little information exists on the natural history and pest University, and vouchers are deposited in the University of Nebraska potential of C. crinicornis. Adults are most commonly found in corn, State Museum. Zea mays L., and soybean, Glycine max (L.) Merrill, fields from June Oviposition Containers. A male and a female C. crinicornis were through August in southeastern Nebraska (Miwa 2014) although low placed in each polystyrene oviposition container with silty clay loam densities occur outside of crop habitats (K.M., personal observation). soil and an adult food source. Containers were similar in design to that Moreover, adult C. crinicornis emerge from both corn and soybean described by Campbell and Meinke (2010) and were 5.9 cm by 5.9 cm fields and readily feed on leaves of both crops (Miwa 2014). by 7.8 cm (length by width by height) with a 0.6-cm deep lid Because of the increasing awareness of C. crinicornis by growers in (ShowMan Box, Althor Products, Windsor Locks, CT). Soil was sifted production agriculture, a proactive approach has been taken to under- through a 60-mesh sieve and then autoclaved. Approximately 50 ml of stand the natural history and pest potential of this species. As part of a soil was placed in each container as an oviposition medium, and the soil larger, comprehensive study, this article reports the results of laboratory was moistened with distilled water (about 27% moisture by volume). VC The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work properly cited. For commercial re-use, please contact [email protected] 2 JOURNAL OF INSECT SCIENCE VOLUME 15 pretense L., and alfalfa, Medicago sativa L.). However, most of these attempts resulted in little to no success. Based on results obtained in 2010, improved rearing methods were established in 2011and are reported in this article. Thirty neonate larvae were placed in each larval rearing container, which was a 59-cm2 plastic cup with a lid (Solo Plastic Souffle Portion Cups, Solo Cup Company, Lake Forest, IL). Peat moss was used as the substrate and was sifted through a 4-mesh sieve before being autoclaved. Distilled water (20% moisture by vol- ume) was added to peat moss in a larger container to prepare substrate for multiple larval rearing containers. Because larvae appeared to have difficulty moving if the substrate was loose, moist peat moss was com- pressed and filled to two-thirds the height of each container. Two germi- nated corn seeds (Pioneer Brand hybrid 34A15) were placed in each container. Five pin holes were made on each lid to allow slight ventila- tion. Containers were incubated at 23.0 6 1.7C for approximately 7 d to allow corn roots to grow inside containers before larvae were intro- duced. Two germinated corn seeds were added approximately every 10 d to adequately provide fresh roots for larvae. After 30 d, larvae were Fig. 1. An adult C. crinicornis collected in southeastern Nebraska in placed in new containers with fresh peat moss and germinated corn 2012. seeds. In 2011, larval survival was recorded at 30-day intervals for up to 270 d after larval eclosion. Head capsule width at the widest point and body length were measured 30, 60, and 90 d after larval eclosion. The soil was mixed in the container creating variously sized soil clumps Mature Larvae, Pupae, and New Adults. To study the late larval as preliminary experiments indicated that C. crinicornis seldom stage, pupal stage, and early adult stage in the laboratory, overwintering oviposited in compacted soil with a smooth surface. Because adult larvae were collected in cornfields in May and June 2012 at the C.