Taxonomic Revision and Biocontrol of Bruchidius lineolatus Arora (Coleoptera: Bruchidae)

Vinay Katoch1* and D. R. Thakur2

1& 2 Department of Biosciences, Himachal Pradesh University, Shimla - 5, INDI A

* Correspondance: E-mail: vinaykatoch84@gmail.com

(Received 28 July, 2017; Accepted 21 Sept, 2017; Published 07Oct, 2017 )

ABSTRACT: Insects are grouped in 30 orders of class Insecta, out of which 9 are very destructive and act as pests of plants and animals. The largest number of described species is in the order Coleoptera. Bruchidae is a small family of this order with 2000 known species but it has a significant economic importance. Bruchids are seed borers and attack on wild leguminous hosts in field and the edible legumes in stores. All the known beetles of family Bruchidae feed on seeds of 34 families of kingdom Plantae and about 80% of them feed on the seeds belonging to family Fabaceae. Bruchids attacking green pods of wild legumes are usually univoltine, has specific but long developmental period and life span. These are generally referred as field bruchids. Bruchids are universal beetle infest leguminous plant and their larvae entering the seed and feed on cotyledons and embryo and rendering them nonviable. Under the present investigationBruchidius lineolatus Arora has been found associated with Albizzia procera Roxb. in different parts of Himachal Pradesh, India.

Keywords: Bruchidius lineolatus; Albizzia procera; taxonomy; entomophagous; control.


INTRODUCTION: Order Coleoptera of class Insecta has the largest number of described species worldwide. Family Bruchidae of order Coleoptera is a small but economically important. Bruchidae belongs to the super family Chrysomeloidae which includes Cerambycidae and Chrysomelidae and is characterized by pseudotetramerous tarsi. Bruchids are small sized mostly dimorphic insects but most of them are injurious pests of green pods, ripe pods and stored seeds of family Leguminousae. Bruchidae comprises a small family having 70 genera under five sub families viz. Amblycerinae, Bruchinae, Eubaptinae, Kytorhininae, Pachymerinae and subfamily Bruchinae is the largest among all. Many species have obvious economic importance because they breed on grain legumes and consume valuable proteins that would otherwise be eaten by human beings. Several genera like Bruchidius, Callosobruchus, Caryedon, Conicobruchus infest wide range of host plants andBruchus, Bruchidius, Sulcobruchus, Conicobruchus and Specularis are univoltine and attack the green pods of edible and wild legumes. A. procera is medicinally an important plant, and widely distributed throughout the greater part of India except the most humid, cold and the driest region. Under the present investigationB. lineolatus Arora has been found associated with Albizzia procera (L.F.) Roxb. in different regions of Himachal Pradesh. Along with the emergence of adult bruchids, some larval and egg hymenopteran parasitoids have been observed. A larval parasitoid, Entedon albiziarum Rasplus (Hymenoptera: Entedontinae: Eulophidae) has been identified. There are about 170 described species of genus Entedon globally but only five species viz. E. gunturensis Shafee and Rigvi, E. longicorpus Khan and Shafee, E. pempheridis Ferriere, E. thoubalensis Chisti & Shafee and E. albiziarum has been recorded so far. E. albiziarum has been found parasitizing the larval stages ofB. lineolatus and play an important role in biological control.

MATERIAL AND METHODS:

Collection of pods: Pods of A. procera infested with B. lineolatus were collected from the different regions of Himachal Pradesh from an altitude 350 to 1600 meters above mean sea level. The pods were carried from the field to the laboratory in wire mess cages. The wire mess cages were kept in the BOD in laboratory at 25C and 65% relative humidity.

Slide preparation : The sacrificed adult specimens were treated with hot 10% KOH, and then washed with distilled water for four or five times. Taxonomical useful parts were treated different grades of alcohol and finally mounted in DPX. But host and parasitoid were identified after running the specimen in dichotomous taxonomic keys.

Illustrations: Illustrations were drawn with the help of graph eyepiece fitted in stereoscopic binocular microscope. Photographs of insect and pods both in field and laboratory were taken with help of Nikon D-80 and Olympus camera fitted on stereoscopic trinocular zoom microscope.

Measurements: Measurements were taken by standardizing the micrometer with eyepiece micrometer fitted in microscope. Scale line of 0.1 mm for genitalia and 1.0 mm for morphological characters were taken.

RESULTS AND DISCUSSION:

Bruchidius Schilsky, 1905

Bruchidius Schilsky , 1905, Kaef. Eur., 41:8. Type species: B. quinqueguttatus (Ol.).

Pronotum is sub conical, antennae are long, surpassing the base of pronotum. Hind femur canaliculate below, with a minute preapical tooth on the inner carina ventrally, not accompanied by smaller teeth.

Bruchidius lineolatus Arora

Bruchidius lineolatus Arora, 1977, Oriental Insects Suppl., 7: 1:32.

Holotype?, allotype? , India: Himachal Pradesh: Biajnath, xi. 1964 collected from Albizzia procera (Roxb). Benth (Kala Sarin) (Family: Leguminosae).

The B. lineolatus has been found associated with A. procera in different regions of Himachal Pradesh causes serious damage to its seeds thus reduces the natural propagation of this important plant in Himachal Pradesh, India. The bruchid species attacking green pods of wild legumes are usually univolitine, host specific and have short developmental period and life span. The present work has been done to explore the nature of association of B. lineolatus with A. procera. Studies were also included on the ecological status of the pest species and to know the parasitoid species associated with host insect.

Material studied :

Paratypes: 5 ?, 6 ?, Himachal Pradesh: Hamirpur: Kathulag, v. 2015. Paratypes: 6 ?, 3 ?, Himachal Pradesh: Bilaspur: Jhanduta, iii. 2015. Paratypes: 4 ?, 2 ?, Himachal Pradesh: Kangra: Dhameta, iv. 2015. Paratypes: 8 ?, 7 ?, Himachal Pradesh: Una: Lathiani, v. 2015. Paratypes: 6 ?, 4 ?, Himachal Pradesh: Solan: Bhrarighat, xi. 2015.

Morphological characters:

Male and female are not morphologically differentiated. Length and width of male and female adult is about 3.63 to 4.09 mm and 2.97 to 4.29 mm respectively (Figure 1). Head is black broader and constricted at posterior end. Frons is carinate. Head surface is covered over with yellowish setae. Eyes are small, bulging and emerginate. Canthus is shallow and narrow and also covered with white setae. Antennae are short not surpassing the pronotum, subserrate, testaceous, 11 segmented and margin blackish in colour. Antennae do not reaching middle of elytra; antennal segments 1-4 cylindrical, 5- 11 broad blackish yellow. Pronotum is a prominent plate like structure that covers small part of thorax. Pronotum is black, subconical, its surface is pitted, uniformly covered over with scattered white and pale setae which are arranged in a longitudinal narrow line running in the posterior half of pronotum. Scutellum is quadrangular, broader than long and bifid posteriorly. Its surface is adorned with white coloured setae. Elytron is brown, elongated and their surface is covered over with brown setae interspersed by a few lineoles of white setae. Each elytron is having an indistinct bituberculate area at the bases of 3 rd and 4th striae (Figure 2). Pygidium is brown in colour, sub-oblique in both sexes and uniformly covered with short brown setae, with a median line and a posterior spot of prominent setae (Figure 3). All the three pairs of legs are yellowish, tips of tarsi black and hind leg is larger than middle and foreleg. Fore and middle legs are testaceous except the black coxae, hind femura and tibia is dark brown. Hind femur is bicarinate below, inner carina is with a pre apical tooth (Figure 4).

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Figure 1: Adult female of B. lineolatus.

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Figure 2: Elytra of B. lineolatus.

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Figure 3: Pygidium of B. lineolatus.

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Figure 4: Hind leg of B. lineolatus.

Male genitalia : Phallus is long about 0.78 mm. long. Parameres (lateral lobes) are fused at their base up to 1/3rd of their total length, tips of parameres are flattened each carrying about 7-9 setae. Endophallus is thick and provided with minute tubercles; exophalic valve is conical (Figure 5 A).

Measurement: Length of male genitalia is 0.78 mm, width of male genitalia is 0.18 mm.

Spermatheca: Spermatheca is species specific; two lobes of spermatheca are typically bilobed with the distal lobe narrower and shorter than proximal (Figure 5 B).

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Figure 5: (A) Male genital organ of Bruchidius lineolatus (I-Epimere, II- Hypomere, III- Endophalic plates, IV- Exophallic apodeme, V- Phallobase, VI- Exophallus, VII- Paramere, VIII- Exophalic valve), (B) Spermatheca of Bruchidius lineolatus.

B. lineolatus is a univolitine species and lays eggs on the green mature pods of Albizzia procera. There is no sexual dimorphism and male generally mates once time in the life cycle. Egg laying starts in the end of February and during the beginning of March. Eggs are laid on the green and mature pods of host, A. procera. Eggs are laid singly on the outgrowth of the seed in the pod and one egg is deposited and manipulated in about 30 45 seconds. First instar larva penetrate with the help of prothoracic plate into the seed and start eating of the cotyledons and embryo of seeds (Figure 6 A). Whole seed is damaged or consumed by the larval stages of the pest and made unfit for propagation of the plant (Figure 6 B). Emergence of adults starts after winter generally during month of April. Maximum emergence of adults occurs in month of April due to the favorable environmental conditions. Adults make a circular whole in the pod wall after completing their life cycle (Figure 8). Adults were strong flier and remained active most of the time. They were frequently seen to feign death when disturbed, retracted their legs and antennae but resumed normal activity after a short while. Male searched for female to inseminate and female store viable sperm in spermatheca. Along with the emergence of adult bruchids, a larval parasitoid E. albiziarum Rasplus belonging to subfamily Entedontinae, family Eulophidae has also been recorded (Fig. 9 A, B). This bio-controlling agent plays an important role in the suppression of the pest population in the field. Larval parasitoids, E. albiziarum infested and grew inside the larvae of host insect (Figure 7 A). This parasitoid destroyed the developing stages of bruchid thus controlling the propagation of pest. Along with the emergence of pest, parasitoids were emerged after completing their larval cycle on the host larvae. Parasitoid emerged by making a minute circular hole in the developing seeds and pods of A. procera (Figure 7 B, Figure 8).

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Figure 6: (A) & (B) Showing seed damage of A. procera by larva of B. lineolatus.

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Figure 7: (A) Developing parasitoid on larva of B. lineolatus in the seeds of A. procera (B) Parasitoids made hole in the seeds of A. procera for their emergence.

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Figure 8: Small hole made by emerging parasitoids and large hole made by emerging adult of B. lineolatus on the pods of A. procera.

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Figure 9: Adults of Entedon albiziarum; A male, B-female.

The present investigation will help to know the infestation level of A. procera by bruchid species. Investigations also highlight and gave the importance of parasitoid for the biological control of pest which is biological safe, economically feasible and ecological viable and not only reduce the load of hazardous chemicals but also useful to maintain the ecological balance in the nature.

DISCUSSION : B. lineolatus has been reported on the seeds of A. procera from different regions of the Himachal Pradesh. 48 species of bruchids belonging to different genera has been recorded from North West India out of which 23 species belong to genus Bruchidius, 8 to Caryedon, 5 to Callosobruchus, 4 to Spermophagus, 2 each to Bruchus, Specularis and Sulcobruchus2. In India, 96 species referable to 10 genera including Bruchidius under 3 sub- families viz. Pachymerinae, Bruchinae and Amblycerinae has been recorded in 2002 2. The head capsule of B. lineolatus was black broader and constricted at posterior end. Frons was carinate. Head surface was covered over with yellowish setae. The external morphology of head capsule of the adults of 39 bruchids species belonging to 9 genera and 3 subfamilies, viz. Bruchinae, Amblycerinae and Pachymerinae and characters of species belonging to genus Bruchidius were comparable with B. lineolatus2-12. Antennae of B. lineolatus were short not surpassing the pronotum, subserrate, testaceous, 11 segmented and margin blackish in colour. Antennae did not reaching middle of elytra; antennal segments 1-4 cylindrical, 5- 11 broad blackish yellow. Similarly results were seen while describing the taxonomy of Bruchidius species from different area1 & 2. Hind femur of B. lineolatus was bicarinate below, inner carina was with a pre apical tooth. 9-12 Description of two new species of genus Bruchidius Schilsky gave the related morphological characters; fore and middle legs testaceus with tips of tarsi and claws black, hind legs entirely black, hind femur bicarinate below and its inner carina with small preapical tooth.In male genitalia, Phallus was long about 0.78 mm. long. Parameres (lateral lobes) were fused at their base up to 1/3 rd of their total length, tips of parameres were flattened each carrying about 7-9 setae. Endophallus was thick and provided with minute tubercles; exophalic valve was conical. 1-4 Description of male genitalia is required in family Bruchidae for taxonomic importance. B. maglorensis and B. brunneus were segregated on the basis of their different male genitalial structures9. On the basis of male genital characters a new species of genus Bruchidius was erected from Albizzia plant from Northern Thailand8-10. Seasonal abundance of adult B. lineolatus was recorded maximum in the month of April. It decreased as the temperature decreases and found lowest in the month of December and January. Seasonal abundance of B. villosus was recorded in North Carolina and noticed that adult weevil could be found on host plants from early April to the end of August2-11. Bruchids were parasitized by many hymenopteran parasitoids and use of these parasitoids for the control of insect pests seems very useful. Under present investigation,E. albiziarum has been found parasitizing the B. flavovirens larvae. Same description of parasitoid - host association of Entedon costalis has been recorded with weevil Glocianus punctiger (Gyllehal)3.

CONCLUSION: The present investigation will help to know the infestation level of pest on A. procera. Investigations also highlight and gave the importance of parasitoid for the biological control of pest which is biological safe, economically feasible and ecological viable and not only reduce the load of hazardous chemicals but also useful to maintain the ecological balance in the nature.

ACKNOWLEDGEMENT: I am very thankful to Desh Raj Thakur, Ashish Mehta (Dept. Of biosciences Himachal Pradesh University Shimla, India) for their valuable help for research material on bruchids and Alex Gumovsky (Schamlhausen Institute of zoology Bogdon, Ukrain) for his useful advice for parasitoid identification.

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12. Toma, L., Ramos, R., Severini, F., Luca, M. D., Mei, M. and Zampetti, M. F. (2017) First record of Bruchidius raddianae infesting Vachellia karro in Italy from Lampedusa Island (Coleoptera: Bruchidae; Fables: Fabaceae). Fragmenta Entomologica, 49(1), 236.