Field survey of Cassidinae beetles (Coleoptera, Chrysomelidae) and their host plants in southern Guangxi, China.

Few systematic studies have been conducted on the faunal composition and food web structure of Cassidinae of China. During 2013-2019, we systematically investigated Cassidinae beetles and their host plants in the southern Guangxi. A total of 2,255 Cassidinae individuals from 66 species, 23 genera and ten tribes were collected in southern Guangxi. Most species belonged to the tribe Hispini (23 species, 34.8%), followed by the tribe Gonophorini (13 species, 19.7%), Cassidini (eight species, 12.1%) and Aspidimorphini (six species, 9.1%). The others (16 species) belonged to the tribes Anisoderini, Botryonopini, Callispini, Oncocephalini, Notosacanthini and Leptispini. The tribe Notosacanthini was recorded from Guangxi for the first time. The genera Neownesia (Botryonopini), Gonophora (Gonophorini), Micrispa (Gonophorini), Notosacantha (Notosacanthini) and Prionispa (Oncocephalini) were firstly recorded in Guangxi. In total, we obtained 47 newly-recorded species in southern Guangxi and 33 newly-recorded species in the whole Guangxi, of which, Callispafrontalis Medvedev, 1992 was newly recorded in China. Dactylispafeae Gestro (625 individuals) and D.chinensis Weise (565 individuals) were the most common species. A total of 69 species, 53 genera and 19 families of host plants were identified for Cassidinae in southern Guangxi. Many host plant associations are new records for Cassidinae. Quantitative food web analysis indicated that Cassidinae species in southern Guangxi primarily fed on Poaceae, Convolvulaceae, Cyperaceae and Rosaceae. Generally, the plant-Cassidinae food webs were moderately complex and stable in southern Guangxi. This is the first large contribution to the knowledge of the species composition and host plant diversity of Cassidinae in southern Guangxi.

The Cassidinae beetles of Longnan County (Jiangxi, China): overview and community composition.

There are few reports on the community composition and diversity pattern of the Cassidinae species of China. Compared to the neighbouring provinces of Guangdong, Fujian and Zhejiang, the Cassidinae richness in Jiangxi Province is under-reported. Longnan City, a biodiversity hotspot in Jiangxi Province, was chosen to obtain the first overview of the Cassidinae beetles. The sample coverage curves for the three sample sites reached an asymptote which indicated sampling was sufficient for data analysis. A total of eight tribes, 16 genera, 59 species and 1590 individuals of Cassidinae beetles were collected. Most belonged to the tribe Hispini (1121 individuals; 70.5%), followed by the tribe Cassidini (161 individuals; 10.13%) and the tribe Oncocephalini (159 individuals; 10.0%). The remainder (149 individuals) belonged to five tribes (Gonophorini, Basiprionotini, Callispini, Notosacanthini and Aspidimorphini). The tribes Notosacanthini, Aspidimorphini and Oncocephalini were newly recorded for Jiangxi Province. There were 14 families, 27 genera and 39 species of host plants of Cassidinae beetles in Longnan County. Cassidinae larvae mainly feed on the plant families Poaceae, Rosaceae, Lamiaceae and Rubiaceae. Most host-plant associations are new reords for the beetle species. This research, together with our planned future work in China, may help to explain the geographical distribution, diversity patterns and host plant associations of these beetles.

Description of immature stages and biological notes of Cassidisparelicta Medvedev, 1957, a newly recorded species from China (Coleoptera, Chrysomelidae, Cassidinae, Hispini).

The first instar and mature larva and pupa of Cassidisparelicta Medvedev, 1957, a newly recorded species from China, are described and figured. The chaetotaxy of the head, mouthparts, legs, and dorsal and ventral surfaces of the body is described. This is the first detailed description of immatures in the genus Cassidispa. Diagnostic characters of this species are compared with other described immatures of some Hispini genera. Biological notes on C.relicta, such as host plants, feeding patterns of adults, structure of larval mines and life history, are also presented.

Description of the last-instar larva and pupa of a leaf-mining hispine - Prionispa champaka Maulik, 1919 (Coleoptera, Chrysomelidae, Cassidinae, Oncocephalini).

The last-instar larva and pupa of Prionispa champaka Maulik, 1919 are described and figured in detail. The chaetotaxy of the head, mouthparts, legs, and dorsal and ventral surfaces of the body are given. The larva of P. champaka mine in the leaves of Pollia japonica Thunb. (Commelinaceae) and pupate in the base of the mid-ribs. The adults were also observed feeding on the leaves of Pollia siamensis (Carib.) Faden ex D. Y. Hong. The prominent diagnostic characters of immature stages of other species of the three genera of Oncocephalini (Prionispa, Chaeridiona, and Oncocephala) are discussed.

Experimental assemblage of novel plant-herbivore interactions: ecological host shifts after 40 million years of isolation.

Geographic isolation is the first step in insect herbivore diet specialization. Such specialization is postulated to increase insect fitness, but may simultaneously reduce insect ability to colonize novel hosts. During the Paleocene-Eocene, plants from the order Zingiberales became isolated either in the Paleotropics or in the Neotropics. During the Cretaceous, rolled-leaf beetles diversified in the Neotropics concurrently with Neotropical Zingiberales. Using a community of Costa Rican rolled-leaf beetles and their Zingiberales host plants as study system, we explored if previous geographic isolation precludes insects to expand their diets to exotic hosts. We recorded interactions between rolled-leaf beetles and native Zingiberales by combining DNA barcodes and field records for 7450 beetles feeding on 3202 host plants. To determine phylogenetic patterns of diet expansions, we set 20 field plots including five exotic Zingiberales, recording beetles feeding on these exotic hosts. In the laboratory, using both native and exotic host plants, we reared a subset of insect species that had expanded their diets to the exotic plants. The original plant-herbivore community comprised 24 beetle species feeding on 35 native hosts, representing 103 plant-herbivore interactions. After exotic host plant introduction, 20% of the beetle species expanded their diets to exotic Zingiberales. Insects only established on exotic hosts that belong to the same plant family as their native hosts. Laboratory experiments show that beetles are able to complete development on these novel hosts. In conclusion, rolled-leaf beetles are pre-adapted to expand their diets to novel host plants even after millions of years of geographic isolation.

Limited tolerance by insects to high temperatures across tropical elevational gradients and the implications of global warming for extinction.

The critical thermal maximum (CTmax), the temperature at which motor control is lost in animals, has the potential to determine if species will tolerate global warming. For insects, tolerance to high temperatures decreases with latitude, suggesting that similar patterns may exist along elevational gradients as well. This study explored how CTmax varies among species and populations of a group of diverse tropical insect herbivores, the rolled-leaf beetles, across both broad and narrow elevational gradients. Data from 6,948 field observations and 8,700 museum specimens were used to map the elevational distributions of rolled-leaf beetles on two mountains in Costa Rica. CTmax was determined for 1,252 individual beetles representing all populations across the gradients. Initial morphological identifications suggested a total of 26 species with populations at different elevations displaying contrasting upper thermal limits. However, compared with morphological identifications, DNA barcodes (cytochrome oxidase I) revealed significant cryptic species diversity. DNA barcodes identified 42 species and haplotypes across 11 species complexes. These 42 species displayed much narrower elevational distributions and values of CTmax than the 26 morphologically defined species. In general, species found at middle elevations and on mountaintops are less tolerant to high temperatures than species restricted to lowland habitats. Species with broad elevational distributions display high CTmax throughout their ranges. We found no significant phylogenetic signal in CTmax, geography, or elevational range. The narrow variance in CTmax values for most rolled-leaf beetles, especially high-elevation species, suggests that the risk of extinction of insects may be substantial under some projected rates of global warming.

A new species of bromeliad-feeding Cephaloleia Chevrolat (Coleoptera, Chrysomelidae, Cassidinae) from Costa Rica: evidence from DNA barcodes, larval and adult morphology and insect diets.

The Neotropical genus Cephaloleia Chevrolat (Coleoptera: Chrysomelidae: Cassidinae) includes 214 species distributed from the south of Mexico to Argentina. Cephaloleia beetles feed mostly on plants from the order Zingiberales. The interactions between Cephaloleia beetles and their Zingiberales host plants is proposed as one of the oldest and most conservative associations. Here we describe a new species of Cephaloleia (Cephaloleiakuprewiczae sp. n.) that feeds on two species of bromeliads (Pitcairniaarcuata and Pitcairniabrittoniana, Bromeliaceae: Pitcairnioideae). Cephaloleiakuprewiczae was previously described as Cephaloleiahistrionica. This study includes evidence from DNA barcodes (COI), larval and adult morphology and insect diets that separates Cephaloleiakuprewiczae from Cephaloleiahistrionica as a new species.

The genus Cephaloleia Chevrolat, 1836 (Coleoptera, Chrysomelidae, Cassidinae).

The species of the Neotropical genus Cephaloleia Chevrolat, 1836 are revised. We present a key to the known larvae of Cephaloleia (8 species), a key to the 95 species known to occur in Mexico, Central America and the West Indies, and a key to the 138 species known to occur in South America. All identification keys were translated to Spanish. Descriptions for the 214 known species of Cephaloleia as well as illustrations for 212 species are presented. The following species are removed from Cephaloleia: C. bipartita Pic, 1926c is transferred to Hybosispa Weise, 1910; C. minasensis Pic, 1931 and C. viridis Pic, 1931 are transferred to Stenispa Baly, 1858. The following species are described as new: C. abdita sp. n. from Brazil; C. amba sp. n. from Colombia, Ecuador, and Peru; C. angustacollis sp. n. from Ecuador; C. brevis sp. n. from French Guiana; C. calathae sp. n. from Costa Rica; C. chica sp. n. from Peru; C. conforma sp. n. from Costa Rica; C. crenulata sp. n. from Ecuador; C. gemma sp. n. from Bolivia and Brazil; C. horvitzae sp. n. from French Guiana; C. interrupta sp. n. from Costa Rica; C. kressi sp. n. from Costa Rica; C. lenticula sp. n. from Ecuador, French Guiana, Peru, and Suriname; C. nana sp. n. from Ecuador; C. ochra sp. n. from Ecuador; C. stainesi sp. n. from Costa Rica; and C. susanae sp. n. from Brazil and Ecuador. Cephaloleia simoni Pic, 1934 is treated as Incertae sedis. The larvae of C. erichsonii Baly, 1858 and C. puncticollis Baly, 1885 are described and illustrated.

Tropical plant-herbivore networks: reconstructing species interactions using DNA barcodes.

Plants and their associated insect herbivores, represent more than 50% of all known species on earth. The first step in understanding the mechanisms generating and maintaining this important component of biodiversity is to identify plant-herbivore associations. In this study we determined insect-host plant associations for an entire guild of insect herbivores using plant DNA extracted from insect gut contents. Over two years, in a tropical rain forest in Costa Rica (La Selva Biological Station), we recorded the full diet breadth of rolled-leaf beetles, a group of herbivores that feed on plants in the order Zingiberales. Field observations were used to determine the accuracy of diet identifications using a three-locus DNA barcode (rbcL, trnH-psbA and ITS2). Using extraction techniques for ancient DNA, we obtained high-quality sequences for two of these loci from gut contents (rbcL and ITS2). Sequences were then compared to a comprehensive DNA barcode library of the Zingiberales. The rbcL locus identified host plants to family (success/sequence = 58.8%) and genus (success/sequence = 47%). For all Zingiberales except Heliconiaceae, ITS2 successfully identified host plants to genus (success/sequence = 67.1%) and species (success/sequence = 61.6%). Kindt's sampling estimates suggest that by collecting ca. four individuals representing each plant-herbivore interaction, 99% of all host associations included in this study can be identified to genus. For plants that amplified ITS2, 99% of the hosts can be identified to species after collecting at least four individuals representing each interaction. Our study demonstrates that host plant identifications at the species-level using DNA barcodes are feasible, cost-effective, and reliable, and that reconstructing plant-herbivore networks with these methods will become the standard for a detailed understanding of these interactions.

Hispines (chrysomelidae, cassidinae) of la selva biological station, costa rica.

Survey work from 1992-2001 identified 139 species of hispines at the lowland part of La Selva Biological Station, Costa Rica. The tribe Cephaloleiini was the most speciose with 58 species (41.7%) followed by the Chalepini with 55 (39.5%). The fauna is most closely related to that in South America but with some genera which are more speciose in the Nearctic Region. Plant associations are known for 88 (63.3%) of the species but many of these are merely collecting records, not host plant associations. The first plant associations are reported for Alurnus ornatus, Alurnus salvini, and Acentroptera nevermanni.