Morphological and Ecological study of Genus Cryptocephalus (Coleoptera: Chrysomelidae: Cryptocephalinae) from Korea
Seung Ho Kang
1and Jong Eun Lee
2*
1National Park Research Institute, Wonju 26441, Korea
2Department of Biology, Andong University, Andong 36729, Korea
한국산 Cryptocephalus 속 (딱정벌레목: 잎벌레과: 잎벌레아과) 의 형태학적 및 생태학적 연구
강승호
1·이종은2*1국립공원관리공단 국립공원연구원
2안동대학교 생명과학과
Abstract :Genus Cryptocephalus are recorded 31 species in Korea. Eggs are oval, coated with faeces. Larvae have J- shaped and it’s last 4-5 abdominal segments directed forwards. Head deeply pigmented and strongly sclerotized. Mouth part is hypognathous. Pupae are compact, protected in cases and head invisible when viewed dorsally. Adults are robust, cylindrical and compact. Adults head invisible when viewed dorsally and antennae filiform. Genus Cryptocephalus have unique ecological habit: larvae feed on dead vegetable material and case-bearer females envelop surface of eggs with their excrement.
Key words :Chrysomelidae, Cryptocephalus, Case-bearers, Ecology, Morphology
요 약 :Cryptocephalus속은 한국에 31종이 기록되어있다. 알은 타원형이고 똥과 같은 물질로 감싸져 있다. 유충은 J자 모양이며 배마디 끝의 4-5마디는 앞쪽으로 굽혀져 있다. 머리는 짙은 색이며 딱딱하게 경화되어 있다. 구기는 하구 식이다. 번데기는 치밀하게 뭉쳐 있으며, 케이스에 의해 보호되고 있고 머리부위는 등면에서 봤을 경우 보이지 않는다.
성충은 탄탄하며 원통형으로 치밀하다. 성충의 머리는 등면에서 봤을 때 보이지않으며, 안테나는 실모양이다.
Cryptocephalus 속은 특별한 생태적 특징을 가지는데 유충은 죽은 식물과 같은 유기물을 먹고 유충은 케이스를 지고 살며 암컷은 자신의 알을 분비물로 감싸면서 산란한다.
주요어 :잎벌레, Cryptocephalus, Case-bearers, 생태, 형태
Introduction
The genus Cryptocephalus Geoffroy is a cosmopolitan taxon with more than 1,000 species. There are 398 species known in the Palaearctic region (Loparin & Dovgailo 2002).
In korea, 32 species recorded (Paek et al. 2010; Lee and An 2001). Cryptocephalus belonging to Cryptocephalinae.
Cryptocephalinae are currently divided into three tribes these are Cryptocephalini, Chalamisini, and Clytrini (Reid 1995).
Cryptocephalus commonly referred to “Case-bearers”
because their species build hard cases of faeces which are
mixed with anal and oral fluids in immature stages. Crypto- cephalus larvae have unique ecological habit. The larvae are apparently all case bearers, and most of them feed on dead plant materials on the surface of the soil. Although larval stages are important and the longest part of the life cycle, very little is very little have known. Genus Cryptocephalus adults are robust, cylindrical and compact beetles measuring between 2-7 mm long.
There is very little study (all study are adult’s taxonomic description) conducted about Cryptocephalus in Korea. So, This study aims to explain detailed larval characteristics of
*Corresponding author E-mail: [email protected]
Cryptocephalus and to provide some photos related with general morphology of eggs, larvae, pupae. In addition, we provides ecological information of Genus Cryptocephalus.
Materials and Methods
The species used in this study are collected and observed in April (2011) – Agust (2013) at Korea, mostly wet land and riverside. Adults can be found their respective host plants.
Adults collected from survey sites were being kept in insect breeding dish (10 cm diameter, 4 cm deep) with leaves of host plants, wet filter paper on bottom and checked periodically (Figure 1). Adults are preserved with dried specimen. Eggs, larvae, pupae, larval-case specimens used in the study were preserved in 70% ethanol. 9 species (Crypto- cephalus hyacinthinus, C. confusus, C. koltzei, C. luridipennis, C. nigrofasciatus, C. parvulus, C. sagamensis, C. limbellus,
C. elegantulus) are successfully breeded.
For morphological studies of minute structures, adults observed using Leica M125 (Leica, Germany) microscopes and some larvae were dissected (head, lower mouth part, legs, mandible, notum), cleared in 10% NaOH solution, rinsed in distilled water, and then mounted on slides with Swan’s liquid (20g distilled water, 15g gum arabic, 60g chlorhydrate, 3g glucose, and 2g glacial acetic acid) and observation were conducted with Olympus BX50 (Olympus, Japan) and Leica M125 microscopes with Camera attachment (DP25; Olympus). And descriptions and illustrations were using image analysis program (iSolution lite, ver. 9.1).
The terminology using this study refered Anderson (1947), Takizawa (1976) and Lesage (1984).
Results and Discussion
Figure 1. Cryptocephalus larvae in insect breeding dish. Insect breeding dish (left), feeding decayed leaf (right).
Table 1. Check list of Cryptocephalus from Korea.
Subfamily Cryptocephalinae Tribe Cryptocephalini
Genus Cryptocephalus Geoffroy, 1762
C. aeneoblitus Takizawa, 1975 C. limbellus semenovi Weise, 1889 C. bilineatus Linnaeus, 1767 C. luridipennis luridipennis Suffrian, 1854 C. bipunctatus cautus Weise, 1893 C. mannerheimi Gebler, 1825
C. coerulans Marseul, 1875 C.multiplex multiplex Suffrian, 1860 C. confusus Suffrian, 1854 C. nigrofasciatus Jacoby, 1885
C. coryli (Linné, 1758) C. ochroloma Gebler, 1830
C. difformis Jacoby, 1885 C. parvulus Müller, 1776
C. elegantulus Gravenhorst, 1807 C. peliopterus peliopterus Solsky, 1872 C. exiguus amiculus Baly, 1873 C. pseudopopuli Schöller 2011 C. flavoscutellaris Medvedev, 1973 C. regalis regalis Gebler, 1830
C. fulvus Goeze, 1777 C. sagamensis Tomov, 1982
C. hirtipennis Faldermann, 1835 C. sexpunctatus sexpunctatus Linnaeus, 1758 C. hyacinthinus Suffrian, 1860 C. splendens Kraatz, 1879
C. koltzei koltzei Weise, 1887 C. tetradecaspilotus Baly, 1873 C. kulibini kulibini Gebler, 1832 C. tetrathyrus Solsky, 1872 C. limbellus semenovi Weise, 1889
◎ Cryptocephalus
In the literature (Paek et al. 2010; Lee and An 2001), 32 species of Cryptocephalus are recoreded in Korea. But two species are synonymized ‘C. exiguous Schneider, C. approxi- mates Blay’ and new species ‘C. (Burlinius) pseudopopuli n.sp.’ published 2011 in Korea (Schöller 2011). Consequently 31 species are recorded in Korea (Table 1).
◎ Morphological characteristics of Genus Cryptocephalus (Figure 2)
Eggs (Figure 2-1)
Length 0.7-1.4 mm, width 0.4-1.0 mm (9 species, 45 individuals) Oval, coated with feces, brown.
Mature Larvae (Figure 2-2, 3)
Body length: 2.0-7.6 mm. Head width: 0.4-1.5 mm (9 species, 46 individuals).
Head and Prothorax tubercles brownish. Labrum yellowish.
Head deeply pigmented; strongly sclerotized and flattened, with angular lateral margins forming keel behind frontal suture; coronal suture and Frontal suture distinct, broadly divergent and evenly curved; endocarina absent. Stemmata well developed, 6 in number, distributed in 2 groups, 4 pairs of posterior stemmata behind antenna and 2 pairs of anterior stemmata below antennal bases. Five pairs of dorsal epicranial setae located on near frontal suture. Frons with 6 pairs of frontal setae arranged in 4 transverse rows. Mouth is hypognathous. Clypeus fused with frons and completely fused with labrum, lighter in color than epicranium. Labrum slightly sclerotized; with 4 pairs of labral setae and 1 pair of labral sensilla. Epipharynx with 7-8 pairs of epipharyngeal setae. Antenna 3-segmented, relatively small, segment 2 with a membranous conical sensory papilla. Mandible robust, dark black anteriorly, yellowish brown posteriorly; with 3-4 teeth,
Figure 2. Egg (1), mature larva (2), case (3), pupa and cocoon (4), Adult (5) of Cryptocephalus.
two mandibular setae on outer edge.
Labium. Postementum with 3 pairs of setae and 1 pair of sensilla. Ligula with 2 pairs of setae. Labial palpifer with 1 setae; Left and right palpifers fused at base. Labial palp 2- segmented.
Maxilla. Maxillary palp 4-segmented. Stipes with 2-3 setae
and anumerous lateral spinules. Lacinia fused with stipes;
with 2 setae. Galea with 10-12 setae. Cardo with 1 seta.
Thorax. Pronotum well sclerotized. Mesothoracic spiracles situated on epipleural anterior (EPa) part. Meso- and meta- thorax with tubercles or not.
Legs elongated and without puvillus. Tarsungulus mode-
Figure 3. General morphology of Genus Cryptocephalus mature larva(A: habitus (l.v.), B: head (d.v.), C: lower mouth part (v.v.), D: leg (l.v.), E: spiracle (d.v.), F: mandible (v.v.), G: antenna (d.v.).
9 setae.
Abdomen. Strongly bent forward, J-shaped, not sclerotized, broadcast at 6th and 7th abdominal segments. Spiracles present on segments 1-8; similar to mesothoracic spiracles but smaller.
Laval case (Figure 2-3)
Length 2.4-7.6 mm (9 species, 46 individuals). Larger than larva. Dark brown.
Pupae (Figure 2-4)
Length 2.3-7.0mm (3 species, 6 individuals). Compact.
protected in cases. All of body creamy white, head invisible when viewed dorsally and two pairs of wing visible.
Adults (Figure 2-5)
Robust, Cylindrical and compact measuring between 2-10 mm long.
Head partially or completely concealed within the prothorax when viewed dorsally(hence their name); antennae filiform 11 segments, antennae with segments 7-10 at least one and a half times as long as broad, not thickened towards apex.
Body base of the pronotum as wide as base of the elytra;
seventh abdominal tergite usually visible beyond the elytra.
The elytra of cryptocephalus bear distinct rows of punctures, which are sometimes useful diagnostically. The female has central fovea on the last (fifth) visible andominal sternum.
Front edge of prosternum lateral to each coxa straight.
pronotum crenulate at its base. Leg claws simple.
◎ Ecological study
Larvae protect their weak body with sclerotized head and faecal cases so that defend from predator or parasitoid.
However, 20 of 23 larvae captured in field are parasited by parasitoid (Ichneumonidae).
Case-bearer
The larval-case is a maternally initiated (egg case) protective home (moveable house) that covers most of the body with only the legs and head projecting from the base opening, enabling movement and feeding. The sclerotized head fits inside the case relatively tightly so that, when it is withdrawn, the access of predators or parasitoids to the non- sclerotized, soft body of the larva within is much restircted.
As the larva grows, it expands the case longitudinally by applying its faeces to extend the basal margins. Case materials comprise primarily faeces. The faeces are hard and dry, and are packed very densely.
Host-plant (Table 2)
Table 2. Host plants of Genus Cryptocephalus (Underline means newly identified host plant).
Species Host plants
C. aeneoblitus Takizawa Reynoutria japonica, Salix spp., Betula tauschii, Betula spp., Carpinus sp., Rhododendron schlippenbachii, Quercus serrata, Castanea crenata, Lespedeza spp.
C. exiguus amiculus Baly Malus pumila, Pyrus pyrifolia var. culta, Castanea crenata, Q. serrata, Lespedeza bicolor, Lespedeza cyrtobotrya
C. bilineatus (linné) Artemisia princepas, M. pumila.
C. bipunctatus cautus Weise Salix spp.
C. limbellus semenovi Weise Artemisia. Princeps
C. confusus Suffrian Alnus firma, Q. serrata, Q. acutissima, Lespedeza spp.
C. elegantulus Gravenhorst Artemisia princeps C. fulvus Goeze Artemisia. capillaries
C. hyacinthinus Suffrian Rosa hybrid, Castanea crenata, Q. serrata, Q. acutissima, Lespedeza bicolor
C. peliopterus Solsky R. japonica, Alnus hirsuta, Q. dentata, Q. acutissima, Q. serrata, Castanea crenata, Lespedeza bicolor C. koltzei koltzei Weise Artemisia. princeps, Lespedeza bicolor
C. luridipennis Suffrian Salix spp., Alnus japonica, M. sieboldii, Lespedeza spp. Sophora flavescens C. nigrofasciatus Jacoby Salix spp., Salix gracilistvla, B. platyphylla var. japonica, Carpinus sp., Q. serrata C. parvulus Müller Salix spp., Betula platyphylla, Carpinus sp. Q. serrata
C. sagamensis Tomov S. gracilistyla C. sexpunctatus Linné Pupulus sieboldii
C. tetradecaspilotus Baly Lysimachia fortunei, L. clethroides, Lespedeza cyrtobotrya
Figure 4. Central fovea on the females’s abdominal sternum.
Cryptocephalus adults feed on alive leaves and petals.
However, larvae feed on dead plant materials such as dead leaves and branches on the surface of the soil. Surveyd host plants in literature (Lee and Cho 2006) and this study are explained in table. 2.
Oviposition (Figure 4)
The female Cryptocephalus is distinguished from the male by the presence of a central fovea on the last (fifth) visible abdominal sternum (P. Jolivet amd E. Petitpierre 1981). It is here where the egg is rotated while being coated in feces.
Before each egg is released, females individually envelop each egg with several small and tightly packed plates of excrement on a central fovea (Erber 1988). Coated eggs are dropped onto the ground.
Life-cycle
Geuns Cryptocephalus has various life cycles that impacted by temperature, climate and host-plant. Duration of the life cycle is mostly 1 year but that of some species is 2 years.
Cryptocephalus mostly has four larval instars. During larval stage, they feed exclusively on dead or decaying leaves of plants. In the last instar larva stage, they stop feeding and moving deeper in the leaf litter for overwintering (some species are overwintering for eggs). The prepupa (late instar 4) fixes the case to the substrate, closes the base opening with its faeces, and makes a pupal chamber. pupal stage last between 10 and 17 days and emerging from cocoon chewing their cases near the widest point and forcing them open. The adults are shown from the spring to summer. Before mating, they feed on plants around a week. The oviposition period is quite long (7-30 days) and laid eggs per female are 20-300.
The hatching period is 10-15 days in the laboratory.
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