栖境不同的两种跳甲复眼结构比较

栖息于荫暗隐蔽处的蛇莓跳甲(Altica fragariae)和向阳开阔地的萎陵跳甲(A.Ampelophaga)的复眼外部形态及小眼微细结构有如下相同特征：两复眼均比较小，呈“八”字型排列在头部近背方的两侧；每个小眼含有一个双凸面的角膜锥体、4个森氏细胞和7个小网膜细胞；2个主色素细胞及11-12个附色素细胞围绕在小眼的外缘；小网膜细胞和色素细胞内均有丰富色素颗粒，当光照强度发生变化时，小网膜细胞内的色素颗粒发生位移；在视杆中段横切面上，视杆由7个微绒毛呈平行排列的矩形视小杆组成，其中的6个视小杆互相连成一个近似六边形的框架，将另一个视小杆围在中央。两种跳甲复眼结构的主要差异有：蛇莓跳甲每个复眼大约仅有150个小眼，而萎陵跳甲约有2印个；复眼曲率半径前者只有后者的一半；视杆中段横切面上，视杆占整个小网膜面积的比率两虫分别为37%和25%，蛇莓跳甲高于萎陵跳甲。对以上形态结构特征可能具有的功能意义进行了初步讨论。

COMPARATIVE STUDY ON THE STRUCTURE AND CHARACTERISTICS OF COMPOUND EYES OF TWO SISTER SPECIES WITH DIFFERENT HABITAT:Altica fragariae and A. ampelophaga

A comparative study of the structure and characteristics of compound eyes is made with light- and electro-microscopes on two sister species in Chrysomelidae: Altica ftagariae, which is a shade-habiting insect, inhabit in shade and concealed niches, and A. ampelophaga, a light-habiting insect living in sunny and open places.Both species possess ovoid compound eyes with diameter of 0.3 mm in the long direction on the upside laterad of the head' Each ommatidium contains a doubleconvex comeal cone, four semper cells and seven retinula cells, and is surrounded by two principal pigment cells and eleven or twelve secondary pigment cells. Therhabdomeres of six of the seven retinula cells join together and make a hexagonal rhabdom frame with another rhabdomere at the middle. Each rhabdomere is nearlyrectangular in shape and is filled with microvilli arranging nearly in parallel to each other.Aside from these similarities, there are some obvious differences between the two species. The ommatidium number in each compound eye is about one hundred fifty in A. fragariae, but two hundreds in A. ampelOPhaga. The radius of curvature of the compound eye is in the ratio of one (A. fragariae) to two (A. ampelophaga). Theratio of rhabdom occupation to whole retinular area on A. fragarive and A.ampelophaga are about 37% and 25% respectively in the cross section of the middle parts of rhabdoms. The possible functional sitwficance of the structure differences is discussed.