BtIll. IDol. SU",. ttt4la. 1 (1) : 77-80, 1978

FUNCTIONAL RESPONSES OF CAT BARBELS·

K. C. JAYARAM Zoological Survey of India, Calcutta

ABSTRACT barbels are genenilly considered as intended for tactile purposes. Evidences have indicated that the barbels have diverse fuuctions. These gustatory, locomotory. aggressive and sexual aspects are discussed.

INTRODUCTION roidei (sensu Chardon, 1968) have such an elastic axial rod. The epidermis is studded It is well known that all siluriform with cutaneous pear-shaped taste buds. These have barbels ranging from one pair (as in taste buds are found to be more numerous Silonia Swainson, Osteogeniosus Bleeker) to on the apical region than on the basal region, four pairs in number and -from most minute and are with mucus cells and club cells, the (Leiocassis rama (Hamilton)) to as long as presence or absence of either of them being body length, if· not longer in size (Mystus not uncommon. For instance Bogarius baga­ cavasius (Hamilton)). The. maxillary barbels rius (Hamilton) does not have any mucus or which are nearly always the longest are usu­ club cel1s unlike Ompok bimaculatus (Bloch) ally ·befween half and twice the length of the and Heteropneustes fossilis (Bloch) which have head. It has been generally considered that many of these cells. Pfeiffer (1963) con­ these barbels act mainly as feelers for search­ didered club cells as distinct from mucus ing in the' media they live which are secreting cells as the nucleus in the former generally sluggish) ill-lit stream bottoms. lies in the center unlike the latter where it is Diverse functions other than merely of a on the periphrey. Moreover, barbel epidermis tactile nature have come to light which are contains no club cells or only a few very discussed here. small ones, while the body expidermis are abundantly supplied with these cells. STRUCTURE

In investigating the functions of the bar­ Baecker (1926) divided the barbels into bels it becomes necessaty to know their histo­ different categories on the basis of the struc­ logical structure. Sato (1937), Sato and Kapoor ture of the barbel. Thus Ompek bimaculatus (1957), Nagar and Mathur (1958) found that and H eteropneustes fossilis are grouped by the maxillary barbels possess an axial rod of him to be with barbels of the flexible type as cartilagenous tissue. Alexander (1965) found they have an axial rod of carti1aginous tissue. this central rod as a thick sheath of Collagen Other nonsiluriform fishes such as Botia and filres. Ohiot (1976) observed that the Ba.g- Barbus are considered as with barbels of the

------.Paper read before the Sixth Annual C~nference of the Ethol.Qgical Society of India, Bangalore. 78 Bulillin o/Ihl Zoological Su,,,,,, 0/ln4ltJ

tender type since the central core of the maxi­ bottom feeding fishes bear these taste buCts llary barbels in these fishes has only a channel on their 'barbels near the . Herrick for the blood vessel besides nerve fibres. The (1903) demonstrated that in Ictalurus the nose movement of the barbels in these fishes are informs the fish the proximity of food which effected by.the blood vessels becoming turgid is then searched for and located with barbels. unlike in where generally the adduc­ The long barbels on the maxilla cause a tor muscles act as a rotatory axil for the stream of water containing food such as in.. barbels. sects, crustaceans, etc. to come near the mouth by their rotatory movements (Burne, 1909). These observations are substantiate~ by their FUNCTIONS feeding habits. For instance Mystus species feed largely on crustaceans (Kamal Pasha, Gustation :-Taste buds as their name indi­ 1964) ; Ictalurus and Porcus mainly on bottom cate helps in the selection of food items for living invertebrates (Corbet, 1961). Besides these fishes. These are found all over the the maxillary barbels, the mental barbels on body in most catfishes (Bhatti, 1938), but are the ventral side are admirably arranged for plentiful on the barbels. A wide variety of exploring the bottom, near the mouth for

6mm. A

c • lOmm.

Fig. 1. Ventral view of head and anterior part of body of Gagala, ceni" (Hamilton) B Of . vif'idescens (~amilton),. showing the sm.all papillae- like barbels in between the mandibula'r p'air a~d"fh: sieve-like format10n. C. Lateral vie,:, of Phyllotle'".us Iypus. Beulenger showing the leaf-Uk ~ expansIon of the max1llary batbels. e. J.... YAllA.14 : On funt;lional t',spQ.ns,s of call1sh barb~l$ 79 food. In Nangra and Gagata besides the it seems probable this flattened edge acts usual pair, a small pair of papillae-like bar­ as a pad to clear obstacles and also to immo­ bels are found in between, which additionally bilise insects, crustaceans which fOIm the help in discriminating the food. Added. to food-items. these, a stiff sieve-like formation of the in Fright: Pfiffer (1963) based on a number of between skin-fold assist in sievieng extraneous experiments indicated that fright reaction matters. Considering that N angra and Gagata occurred because of release of alarm sub­ are inhabitants of rocky streams, with many stance when the skin is injured and not to pebbles, and sand particles, this adaptation barbel skin. Sato (1937) found of the mandibulary barbels is very striking. anguillaris recognising and reacting mOle by chemical sense such as the release of alarm Locomotion :-Longer barbels of fishes such substance, rather than by the barbels. Even as Pimelodella of South America, Porcus of when the barbels were severed, cognition of Africa, Mystus of India, have a secondary food substances took place. It would thus function to avoid obstacles, before the fish appear that barbels play no part in fright could move into crevices and mud holes in reaction. search of food. Phyllonemus of Tanganyika, Africa has the maxillary barbel flattened like Aggression: However, the barbels are put a leaf at its anterior edges. Though, the out stiffy in an aggressive manner for defense exact nature of this modification is not known, when irritated or';in inescable situations of

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, :~:. ·····~~rA 10 mm. Fig. 2. A ventral view of head and anterior part of body of Bagrichthys hypselopterus Balcker showing the modified inner mandibular barbel. B. Enlarged view of thc barbel to show the cup-like structure with papillae. 80 Bulletin of the Z oologieai Sut'vey of India danger. Day (1878) recorded Mystus vittatus Survey of India for allowing my participation known as the fiddler fish in Mysore to act in the Ethological Society of India's Con­ in this manner. He observed (p. 449) "I ference and to Dr. M. Chardon and Miss. touched one which was on the wet ground, F. Ghiot of Institut edt van Beneden, liege at which it appeared to become very irate, for criticisms. erecting its and making a noise REFERENCES resembling the buzzing of a bee evidently a A~EXANDER, R. Mcn. 1965. Structure and func­ sign of danger. Having put some small tion in the catfish. J. Z 001., 148: 88-162. into an aquarium containing one of these BAECKER, R. 1926 Beitrage zur histologie der fishes it rushed at a small example, seized by Barteinder 1hhche. jahrb. mot'ph. v. Mikrsk. Anal., 6 : 489·[07. the middle of its back and shook it li~e a dog killing a rat, at the time its barbels were BHATTI, H, K. 1938. The integument and dermal akdeton of siluroidea. Trans. zool. Soc. London, stiffened out laterally like a Cat's whiskers". 24: 1-102. batrachus and Heteropneustes Jossilis BREDER, C. M. The reproductive habits of the co~mon catfish A meiurus nebulosus (I.e Sueur) are also known to put out their barbels and with a discussion of their significance in Ontogeny spines stiffly in a defensive or aggressive pos­ and phylogeny. Zoologica, 19 : 143-185. ture when irritated. Fishermen would rathe); BURNE, R. H. 1909. The anatomy of the offac­ cut the meshes of their nets and allow a tory organs of teleostean fishes. Proc. zool. Soc. Londonl 1909 (2)': 610-663. fighting dreadful singi escape with its pectoral fins poised, than dare to handle' it. CORBET, P. S. 1961. The food of non CichUd fishes in Lake Victoria basin, with remarks OD Sexual attraction: Breder (1935) considered their evolution and adaptation to lacustrine con­ ditions. Proc. zool. Soc. Londo", 136 : l-l()l. that tactile stimulation of the barbels played a part in mating of catfishes. Bagr~chthys ClIARDON1 M. 1968. Anatomie comparee de I' appareil de Weber et des structures connexes hypse/opterus from Thailand has the inner chezles siluriformes. Konn. Mus. Midd. Af,ica, mandibular barbels frilled with cup .. like bor.. Telvuren. No. 169: 1·~73,3 pis. ders. Though this also may help in procuring DAY, P. 1878. Fishes of India. Wm. Dawson food, the modification of only the inner

ACKNOWLEDGEMENTS SATO, M., and KAPOOR. B. C. 1957. Histological observations on the barbels of Indian freshwater fishes, Alaska codfish, and Podothalus aciprn­ Thanks are due to the Director, Zoological se"unus. Annot•. zool. Jap., 30 (30) : 156-161.