NO. 7 PROTECTIVE ADAPTATIONS — McATEE 73 



cinellidae, it is easy to see what factor makes for greater depredations 

 by birds ; it is none other than the frequently mentioned " availabihty." 

 Endomychids and Erotylids are red and black or yellow and black 

 beetles, less abundant and much more retiring in habits ; while coc- 

 cinellids with the same colors are more common and live unconcealed. 

 The former are relatively seldom captured, the latter are freely eaten. 

 No better example of the influence of availability in guiding choice of 

 food by birds could be desired. This despite universal acclaim of 

 coccinellids as specially defended insects. "All the lady-birds are very 

 gaily colored " says Donisthorpe. " They boldly walk about with- 

 out any attempt at concealment, as do also their larvae. Both their 

 larvae and pupae are very brightly spotted. The distastefulness of the 

 perfect insects was proved ^ by Jenner Weir, and has since been con- 

 firmed by both Poulton and Wallace." (Trans. Ent. Soc. London, 

 1901, p. 354.) 



Packard states that " The Coccinellidae are .... protected by a 

 yellow mucilaginous disagreeable fluid oozing out of the sides of the 

 thorax," (Journ. N. Y. Ent. Soc, vol. 3, p. 116, 1895), and Wallace 

 says: " The Coccinellidae or lady-l)irds are another uneatable group." 

 (Darwinism, p. 234, 1896.) Let us see. The total numl)er of records 

 of coccinellids in the food of nearctic birds is 1,455 '^"'^ these are 

 shared by 127 species. Twenty-seven kinds of birds had 10 or more 

 records each, nine of which ran over 50, and three over 100. Not only 

 is the effect of availability noted in birds eating mure coccinellids than 

 other similar but less alnmdant and conspicuous beetles, but its 

 influence is evident in at least two other ways, namely that leaf-feeding 

 birds, as warblers and vireos, get the most ladybird beetles, and that 

 in California where coccinellids are notably more abundant than they 

 are in the eastern States, a larger number of birds feed upon them and 

 they get a great many more of the beetles. The largest numbers of 

 coccinellids found in individual stomachs were 12 and 18 taken by 

 English sparrows, 13 by the summer warbler, 14 by the warbling vireo. 

 and 15 by the valley quail. 



We now come to the consideration of three families (the Scara- 

 baeidae and Cetoniidae being reckoned as one ) which Poulton says are 

 "at any rate partially distasteful." Regarding one of these fami- 

 lies, the Lagriidae, which has only 17 species in the nearctic fauna, it 



^ The " proof " was experimental, of course ; for the value of this proof see 

 my 1912 paper. Also note that Meisner's results on the poisonous effect of 

 Coccinellid juices (Ent. Bl. Nurnherg, vol. 5, no. 9, pp. 180-182, Sept. 20, 1909) 

 are controverted by a repetition of his experiments by Heikertinger (Wien. Ent. 

 Zeit., vol. 38, Heft 4-8, pp. 109-113, June 15, 1921). 



