96 
PACIFIC SCIENCE, VoL XV, January 1961 
simple bio-economic structure. Such dishar- 
mony, a common feature of remote oceanic is- 
lands, is also recognized by comparing the num- 
ber of genera and species occurring upon the 
island. Except for birds, the total number of 
families, genera, and species of land animals 
is 54, 70, and 72, respectively. Only seven fam- 
ilies contain more than two species: the Blatti- 
dae (5 spp. ) ; Formicidae (4 spp. ) ; Porcellidae, 
Entomophyridae, Lygaeidae, Noctuidae, and 
Muscidae (2). There are only two genera con- 
taining two species: Periplaneta and Porcellio. 
In connection with this disharmony, it may 
be interesting to consider here the association 
of closely related species, for it has often at- 
tracted the attention of ecologists on account 
of competition or isolation. However, most 
species belonging to families represented by 
more than two species show obvious habitat- 
segregation. Species found in one and the same 
habitat were Leucophanea and Blatta, Anisol- 
abis and Euborella in Ai and D; two species 
of Periplaneta, Lucilia, and Muse a in H; two 
Porcellio in A T ; Sira and Lepidocyrtus in C'i; 
Lasius and Tapinoma almost everywhere. But, 
most of them differ from each other either in 
habit, as in the two ants mentioned above, or 
in their relative abundance in various habitats. 
Those species possessing similar habits, eating 
similar food, and collected from the same hab- 
itat were only two pairs of cosmo- or tropico- 
politan species, Musca and Lucilia, and two Peri- 
planeta. 
In former times, the island offered a favor- 
able breeding site for various sea birds. Sub- 
sequent reckless catching resulted in a rapid 
decrease of both the species and numbers of 
individuals. During our visit, two species, noddy 
terns and sooty terns, still bred on the island. 
Moreover, about 20 golden plovers and five 
American wandering tattlers were seen. Of these 
birds, only the plovers may have an intimate 
relation to the land biota. They were seen 
usually on the surface of the runway or on other 
roads through the E. triangle. According to Ku- 
roda ( in litt. ) , some vegetable matter was 
found in their crops. On the other hand, he did 
not find any food other than cuttlefish in the 
crops of the terns. Therefore, terns and tattlers 
are connected intimately to the marine ecosys- 
tem but possess little relation to land biota. 
Finally, some phenological trends are cited 
here, based upon the experience of the weather 
station staff (especially of Messrs. Y. Nakada 
and K. Fujisawa), as follows: Fructification of 
papaya, September to October; flowering of 
Ipomoea, April, and September to October; 
flowering of Messerschmidia, March to August; 
nymphs of Locus ta, seen throughout the year, 
but abundant during July and August; Dipla- 
codes adults, June to July, and September to 
October; larvae of Herse, throughout year, but 
TABLE 4 
Number of Species Found in Each Habitat 
(Those in parentheses were found exclusively in that habitat.) 
VERTICAL 
DISTRIBU- 
TION 
HORIZONTAL DISTRIBUTION 
TOTAL 
A 
B 
c 
D 
c' 
D' 
H 
1 
2 
3 
27(15) 
14(0) 
20(3) 
13(0) 
7(0) 
9(2) 
19(1) 
10(0) 
20(4) 
10(3) 
3(0) 
1(0) 
45(35 
j-29(9) 
Total 
47(19) 
21(2) 
23(1) 
20(4) 
10(3) 
1 (0) 
Order of richness in number of species: A, D = Art r> Ci > Au > B, > C/ = C a ^ B. t > B a > o>' > d' 
Order of ecological endemicity: A, D > A:; = C? B« > Ci > A« = B, = C a = B a = c»' = d' 
