The Behavior of the Pumpkinseed Sunfish, Lepomis Gibbosus (Linneaus), With Notes On the Behavior of Other Species of Lepomis and the Pigmy Sunfish, Elassoma Evergladei

The sunfishes, family Centrarchidae, inhabit quiet waters of the eastern and southern United States. They feed chiefly on insects, insect larvae, and small crustaceans. The behavior of Lepomis gibbosus, the pumpkinseed sunfish, and Lepomis humilis, the orangespotted sunfish, the two species studied most extensively, is very similar. The behavior of Lepomis macrochirus, the bluegill sunfish; Lepomis auritus, the redbellied sunfish; Lepomis cyanellus, the green sunfish; and Lepomis megalotis, the longeared sunfish, is compared and contrasted to these two where it is known. M a i n t e n a n c e B e h a v i o r. In aquaria Lepomis learn to eat non-living food. L. gibbosus and humilis sleep with ventral surface from chin to pelvic fin insertion touching bottom and all fins maximally spread. The overall body color is darker than during the day. The comfort movements, yawning, body bending, chafing, various fin movements, jerking, mouth snapping, and coughing (listed in order of their frequency of occurrence in gibbosus), occur more frequently in situations of environmental or social stress. A g o n i s t i c B e h a v i o r. The Lateral Threat Display, in which all median fins and the pelvic fins are broadly spread, usually has a defensive function. The Frontal Threat Display is the most aggressive and frequent behavior in the species of Lepomis observed. The displaying gibbosus erects dorsal, anal, and pelvic fins and moves toward an opponent to thrust, rush, swipe, or chase. Of these four variations of the Frontal Threat Display the most complex motivationally is the thrust employed by males in mutual displays on territory boundaries. Biting movements and Opercle Spreads may accompany most forms of frontal threat. Opercle Spreads usually occur at higher levels of aggressiveness than biting movements and often are especially frequent in situations suggesting motivational conflict. Tail Beating is the least frequent agonistic behavior in gibbosus and humilis but occurs commonly in auritus dominance encounters. The Attitude of Inferiority has three components. The first to appear is leaning to one side while swimming. The second to appear is depressed fins, and finally an inferior fish may become darker in color or acquire dark lateral bars on the sides. Social Groups. Differences in group relationships of different species are described. For example, in aquaria in which two male gibbosus established territories and spawned with three or four female companions, groups of auritus and megalotis of approximately the same individual size and sexual composition always were dominated by one individual which eventually killed all companions. Species differences in kinds and frequency of aggressive behavior also exist. Reproductive e B e h a v i o r. The spawning season is marked by the presence of males on shallow, circular nests, the size, structure, and location of which art described for the species studied. Males defend their nests, and since gibbosus, humilis, and macrochirus build nests in groups (with adjacent nest rims), there are many agonistic encounters between neighboring males. In addition to having agonistic encounters males on nests sweep; bite the substrate; push, pull, and carry plants which encroach upon the nest; court females; spawn; fan eggs; and leave the nest temporarily for a variety of reasons. Sweeping, the nest building movement, is done with the caudal fin which moves back and forth much like a broom. In gibbosus sweeping may occur any time before a male spawns but is especially frequent when neighboring males are threatening, sweeping or spawning and when females approach the nest. L. gibbosus ceases to sweep after spawning, but auritus, humilis, and possibly other species sweep after spawning, interspersing sweeping and fanning, which is a post-spawning behavior. L. gibbosus males begin to fan immediately after they spawn and continue to fan vigorously for 18 to 24 hours. Then fanning gradually ceases, and males hover over eggs and larvae. Possible stimuli for initiating and sustaining fanning are described. Courtship behavior occurs when a female ready to spawn approaches a nest. The male becomes very active and his movements are fast and frequent. The body becomes taut with the caudal peduncle arched upwards. The dorsal, anal, and caudal fins are maximally spread. Pelvic fins are depressed. Body color darkens. The male orients his movements toward the female, circles her, and places himself so that the female is directed into the nest. If the female flees the male may swim rapidly back and forth between her and the nest in courtship posture. Substrate biting occurred regularly but did not contribute to nest construction except in auritus. L. auritus males regularly carry stones from the nest to the outside of the nest, but other Lepomis observed did not. When any other activity of the male increased in frequency, the frequency of occurrence of substrate biting also increased. Rim Circling was a behavior observed in nesting male macrochirus but not in gibbosus. Female pre- and post-spawning behavior is described. Spawning occurs when a female swims into a nest and stays. The male and female then assume positions side by side facing in the same direction. With the female on the inside they swim around and around in a small circle barely above the bottom of the nest. At regular intervals the female tilts her dorsum away from the male and while on her side, rubs the ventral surface near her genital pore quickly against the side of his body near the anal fin. As contact is made eggs and sperm may be shed. Many spawning movements produce no eggs. A typical successful gibbosus spawning lasts 25 to 45 minutes. During this time the male may leave the nest many times in Frontal Threat posture and he may attack the female. The behavior of larvae and young fish is described. Elassoma evergladei, a pigmy sunfish, may reach 4 cm. in total length. They inhabit soft, acid waters of the eastern coastal plain of the United States. In aquaria they eat only living food. They have a distinctive sideways approach to food and snap it up. They have no particular sleeping posture and fewer comfort movements than Lepomis. With suitable aquarium conditions and 15-hour daily photoperiod, this species was always in breeding condition and social interaction was common. Lone aquarium inhabitants and non-breeding fish behave similarly. Individuals remain motionless for hours either resting on the bottom or among plants usually in the darkest part of the habitat. They often do not eat even when food is available. Males are territorial. If there is ample bottom space and if males are nearly equal in size and aggressiveness, boundaries are well defined. Otherwise usually one male dominates other companions. There is one threat display and one courtship display. These consist of complicated fin movements, movements of the fish through space, and color changes.