NOTES UPON THE FOOD OF PREDACEOUS BEETLES. * 
• 

BY F. M. WEBSTER. 

Pliny tho11gl1t it nothing to the credit of the philoso-
11l1ers of his day, that while tl1ey were disputing abo11t 
the numl)er of heroes by the 11ame of Hercules, and tl1e 
site of tl1e sepulcher of Baccl111s, tl1ey s11oulc1 11ot l1ave 
been a·ble to decide w hetl1er or 11ot the q11een bee pos­
sessed a sting.1 

While tl1e problem of tl1e l1ee sting· l1as long been de­
ci (l ecl, and heroes by the name of H ercules have ceased to 
t1·011l)le tl1e mi11ds of men, tl1ere are }Jroblems of vital im­
l)or·t ance r egarding tl1e l1abits of tl1e i11sects ,vl1ich, du1--­
i11g tl1e gr·eater 11ortion of tl1e }7 ear, " re meet dail)r i11 
n bun dance, tl1a t still 1--emai11 u11sol,Ted. 

Tl1e most im1Jorta11t a s well a s tl1e most abundant of 
these insects are tl1e beetles. 

While fo11nc1 in almost e,,.e1--y conceivable sit11ation, 
• 

,,Tl1ile our nat11ralists co11nt the species i11 tl1eir cal1inets 
by the tl1ousands, it woulcl be difficult to point 011t a 
single species, tl1e food l1al1its of whicT1 we fitll,y unde1--­
sta11cl, wl1en botl1 tl1e la.r,"a• a11d imago state a1"e talcP11 
1111de1-- co11sidera ti 011. 

Tr11e, ,,Te l1ave a so1,.t of I·it11al laid down by ento1nolo­
g·ist s, l)ased upon tl1e fact that certain species l1ave bee11 
lrnown to feed upo11 certain substances, but tl1is can 110 
more be ronsidered as proof t]1at 11otl1i11g else enterf: into 
tl1eir natl1ral cliet, than does tl1c 1nea,t of wl1icl1 we ma~r 
11a1,.take at clinne1" pro,re 11s to be strictly c.a1·11ivo1 .. ous, 01· 
the bread or f1·uit, that we are exclusively vegeta1·ia11s. 

An illustration of tl1is double diet of beetles is f 01111d i11 
tl1e case of tl1e Et11~opean Silpli a, oprtca,. Linn., tl1e la1·,ra 
of wl1icl1 has been lznown to feed to an injt11"io11s exte11t 
1Jpo11 tl1e leaves of tl1e beet and mangel-w11rzel. 2 

But one of tl1e most fort11nate in g·etting the l1enefit of 
our igno1--ance is tl1e family Caral1idro, to utte1· ,1 worcl 
against vvhiclJ is almost consider·ed c1 sacrilege. 

* A lthou g h this pape1· cl ocs not belong with the s tt1cl ics m itCl e al the 
T..1a borat or y, but j s b ase(1 entire ly upon the author's per sona l obse1· va lions . 
it is inc luderl w ith this series, '\>Vith l1is p e rmissio11 , b ecn.t1se it 1·elates to 
the same subject . Th ese observa ti ons prececl e, in JJOi11t of lin1c , t.l1osc or 
the f o llowing pa.p er.- S. A. 1,,. 

1 Pliny , His t. Nat ., 1. x i, c . t 7. 
2 Curtis, "Farm Insect s,' ' p . 388 . 

• 



N ates it,pon tlie Food of Preda,ceou-s Beetles. 163 

But, true to tl1e adage '' murder will out'', occasionally 
rt species is fo11nd feeding upon vegetation v1ith a vorac­
ity that ,,rot1ld do credit to a Cl11·ysomelid. Of these in 
Europe, besides tl1e Z ab1'·i,ts gibbits i11 botl1 stages, some 
of tl1e Pterostichi, Amarr1r, Omophro11 a11d Cala-tlius latits 
W estw., a1"e said to injt11"e gr·ain l)y eati11g off the yot111g 
sl1oots 01· c1estro3Ting· tl1e seec1.=~ 

Two s1-1ecies of Bembidit1m ( la1npos and 1nonticola) 
l1avTe bee11 dest1~ucti,~e to tl1e fo1"ests of t1ppe1" At1stria.4 

B1,.osci1.s cep1halotes attacks tl1e growi11g g·ra.i11, and 
A1~istits bitceplialits de,Tours tl1e seeds of grass. 5 

In ou1· own cot1nt1"y tl1e Q,11iopliro1i labiatiim Fab. in­
ju1·es tl1e sl1oots of young· co1"n in tl1e Souther11 States. 

JI a1~zJalits caligi,zos-its Fab. is st1spected of feeding upon 
g1"ain in stack in Maryland, ancl also of eating· timotl1y 
seeds from tl1e l1eacls.n 

E. T. Dale, of Jasper, Mo., f 01"vva1·ded to tl1e editors of 
tl1e A1nerica11 Entomolog·ist s1::>ecimens of an insect fot1nc1 
1)3., l1in1 feedin.g upon tl1e seecls of a pla11t u11known to l1im. 
Upo11 examinatio11 they provecl to be H. caliginosits. 1 

Accorcling to 1fr. 11atl1e1", of Ma1,.sl1alltown, Iowa, tl1e 
larvre of some s11ecies of I-Iarpalt1s are destructi,re to l1is 
e,Te-1--g1--eens, lie l1avi11g· fou11d the1n eati11g~ off tl1e roots.8 

Tbe f 01"egoing· is a S)7llOJ)sis of all facts 1·elating· to tl1e 
,reg,etable-feedi11g· Ca1"al1idre, so fa1" as l{no,,1n to tl1e 
autho1" of this 1)a.pe1·. A 11un1ber of years ag'o tl1e w1,.ite1· 
comme11ced tl1e stl1d3r of tl1e f oocl of l1eetles. correctly 
judg·ing· from " rl1at "ras tl1e11 lrnow11, tl1at either natt1ral­
ists we1"e i11 erro1-- in tl1ei1 .. s1111positio11s 01· else that inno­
cent insects ~re1"e wro11g·l~r a(~cusecl. Ancl lie is free to 
co11f ess l1is 1Ja1"tialit~,,:· to the f 01·mer tl1eo1·y as being tl1e 
most co1"rect. But· afte1· se,7 eral 3rears of stt1dy and ob­
se1"vation, I 11a,re fot111d to my astonishment not only tl1e 
species accused l1l1t otl1ers also of this family feedi11g· 
largely u1Jo11 veg·etable st1l.1sta11ces, botl1 11seft1l a11d 11ox­
ious. Among my ea1·liest observatio11s 011 tl1is subject I 

i; Report U. S. Agr. Dept., 1868, pp. 79-80. 
4 Deutsche Entomolog·ische Zeitschrift, 1879, p. 417. 
5 Westwood's 'I'ntrocluction, I, p. 61. " 
6 Report U. S. Agr. Dept., 1868, p. 80. 
7 Am. Ent. Vol. I, p. 80. 
8 Am. Ent. Vol. III. p. 26. 



164 N ates itpon tlie Food of Predaceous Beetles. 

11oted tl1e abunclance of Carabidre about the shocks of 
wheat in a field where a violent wind storm had blow11 
clown a large number of sheaves, under which, upon tl1eir 
being· 1·eplaced; large numbe1--s of H arpalus caligitiosiis, 
1Jennsyl,va,iicits and herbivagits, Pterostichits lucubla11d 1l.'3 

and Anisodactylus balti11iorensis were observed. 
The wl1eat v,ras drawn i11 anc1 th1~eshed di1"ectly fr·on1 

the field, a11d a large percentag·e of the kernels we1"e badly 
ea.ten. P1·evious to the tl11"eshing, in anotl1er field, a 
s1)ecinle11 of H. p1en1,isylvanicits ,vas captured with a pa1"­
tially eate11 g·1"ain of wheat i11 its 1nandibles. Tl1e eate11 
grains of the th1"esl1ec1 wheat seemed to agree with the 
fragments fou11c1 i11 tl1e jaws of tl1e l,eetle, a11d as 110 othe1'" 
destr11ctive ag·encies we1"e noted, tl1e facts seem eel to sug·­
gest that the damage was do11e by tl1e befo1"e-me11tioned 
Carabidre. A few da3rs afte1", H. pen,nsylvan,i,cus ,,ras 
f ou11d eating tl1e 110w fl1lly r·ipe seeds f1"om a l1ead of up-
1·jght timotl1y g·1"ass, a11d was obser,red to detach then1 
from the glurnes. Tl1e same species l1as si11ce l)ee11 see11 
feeding larg·ely upon rag·weed, Ambrosia ar1 teniisicef olia 
Linn., during September,- the seeds apparently bei11g the 
favo1--ite part. A short time a.fte1" it ,,ras f 01.111d upon tim­
otl1y grass it was obse1,.vecl eating. tl1e seeils of p1--airie 
g·rass, Panicii.ni c1·iis-grilli L.; and tl1e sa111e day anothe1· 
indivic1ual was found devol11"i11g a11 I ps f asciat1ts Oliv., 
one of the Nitidulidre, tl1us p1'0,ring its carnivo1 .. 011s p1"'0-

pensities also. H. caliginosits is likewise f ol1nd eating· 
tl1e seeds of A 11ib1·osia arte11i.isicef olia. 

H. herbivagits f eeds larg·ely l1po11 the te11der sl1oots of 
g1·ass d11ring· J\tfa1--cl1, cutting tl1em off j11st below the sur·­
face; but later· it selects the te11de1 .. l1lades a11d tl1c discol­
ored parts usually found 1111cler boards, etc. 

Amara angustata Say is found quite ab1111dantly u1)011 
• 

tl1e heads of J u11e grass, P oa pratensis L. B11t the n1ost 
voracious Carabid ene1ny of this gr·ass is tbc Anisoda.c­
tylus se1,.iceu1s Harris. 

~ 

Early in June, 1878, vast numbers of these beetles wer~e 
11oted upon tl1e l1eads of this g1·ass ; in fact, spots several 
yards in area were literally cove1 .. ed with tben1. Afte1~ 
patient watclJi11g-for tl1ey a1"e , rcr·y timid- the proof' 



• 

N ates it,pon the F ood of Preda,ceous Beetles. 165 

,,-as concl11sive that tl1e l1n1"i1)e seeds were wl1a.t they were 
af te1· and not mic1"osco1')ic. insects as was at first supposed. 

Tl1e i11sect is not only cunning, drawing. llp its legs and 
d1·oppi11g· to tl1e g·1--ol1~d 11pon the least distt1rbance, afte1· 
tl1e ma1111e1" of a. Chrysomelid, but a.lso sl1ows consider­
able ing·e11uity. It gras1)s tl1e lowe1" extremity of the 
g·ll1me tigl1tly in its 1nandibles, then r·elaxing~ slightly, 
11asses l1pwarcl and agai11 tig"l1tens its g·rasp-a series of 
mo,,e111ents which finall)r force the s~ed, whicl1 is no,v of 
the co11siste11cy of cream, ot1t at the apex. This it at once 
l)l"oceeds to devot1r ,,Titl1 a11 a,.l)petite which reminds one 
quite forcibly of a t1"arn1) "'Tl10 l1as l1een oblig·ed to earn 
l1is cli1111e1" in advance. Late1" in tl1e season it is fot1nd 
feeding· i11 tl1e same ma1111e1" U})On the seeds of ~4..qrosti.s 

' 

villgaris ,Vitt. Specime11s of Anisodactylus baltimoren-
sis Sa~'" we1·e ol1se1"vecl feecli11g llpon the marrow ancl 
fa tty matter clinging to tl1e tibia of some dead animal, 
l)I"oba bl3r tl1at of an ox. Attention is called to this as be­
ing i11 11e1·fect accoi"d with microscopic observations re-
11orted b}r M1·. Fo1 .. bes in tl1e following· paper, upon a.11-
othe1· s1)ecimen f 01111d lllJOn grass a few 1nonths later. 

Calct,tliits g1,.egariits Sa)7 may be found ab11ndantl3r upon 
tl1e heads of timothy g1,.ass dl11·ing· tl1e early mornings of 
the first of July. Of tl1e g·e11l1s Platynt1s onl3r a si11gle ob­
sc1""\'"atioJ1 bas bee11 ol)tai11ed, a11d tl1is was c1uri11g tl1e lat­
tr1· })a1"t of ,J u11e of tbe l)I"ese11t )7 ear, wl1en t,,10 specime11s 
of P. c-i1; 1Jripe1i1iis Sa.y ,,Te1 .. e seen l1a1-:assing a half-grown 
c1--icket, which tl1ey l1ad al1"eacly· clisabled. The carnivor­
ot1s l1al~)its of l,eetles a1"e ofte11 as difficult to discover as 
tl1ei1" ,'"eg·etarian. U Sl1all}r tl1e)r are 11ot at all in favor of 
p11blic cli11ners, and, lilce l1easts 01" bircls of prey, prefe1" 
to c1rag tl1eir ,rictims to s01ne secl1,1ded nook to de,rot1r 
tl1en1; l1e11ce, if the obser,re1" gets a11y i11sig·lit into tl1is 
11art of tl1oir domestic affai1·s l1e must tal{e them by st1r­
p1"i:-e. 111 tl1is n1a11ner a Stapliylinit•S ci1inaniopte1'°1ts 
Grav. was surp1"ised wl1ile in the act of de,Touring. a11 

Ano11ioglossils piJ:silli,s Say, ha,ring first, to gt1ard against 
its escape, eate11 off fot1r of its legs. 

In a11otl1er i11stance a Dyschi1·iits globiilosit.<, Say was 
o bse1·ved to spring upon a small salmon-colorecl maggot-



• 

166 Notes it11<>1ri tlie l11uud of P,·edctceous Beetles. 

li]{e la1•,ra, a11cl, afte1" disabling it, to start off to select a 
proper .place to devou1" it. Afte1" the lapse of several 
Jr1inutes, it retur·11ed to clrag· its victim under a s1nall clod 
of dirt and leisurely feast l1pon it. 

After tl1e same man11er· a B1·ct.dycellus 1·iipest,·is Say 
was surprised u11der a sto11e ,,Tl1ile eati11g a small wl1ite 
tl11"ead-like wo1"m. · 

Another family of lJeetles ,,.,l1ose l1itl1e1·to al1nost u11tar-
11isl1ed repl1tatio11 it seems to l1a,re fallen to m3r lot to soil 
is tl1e Coccinelliclre. Witl1 the ·exce1)tio11 of Epilaclina 
bo1·ealis Fab. the larva of ,vhicl1 f eecls l1po11 tl1e , 1i11es of 
tl1e gol1rd f an1il)r, 9 these i11sec.ts in ou1" cot111try l1a,,.e been 
co11side1"ed strictly ca1"ni,"'01·01,1s, although seve1"al E111"0-
l)ea11 s11ecies a1·e l{now11 to clevia te from tl1is rl1le. 

This seaso11, s1)ecime11s of lvl egillct, ,,1zac1tlata DeG. l1a ,Te 
l)een talre11 wlJile feecli11g· 11po11 t]1e 1)olle11 of· tl1e c1a11c1P­
lion, T a·1·a.xac1t 11i de i1 s-lec> 1ii.s, c111c1 it is 11ot at all i1111)1·011-
ftble tl1at tho pollen of otl1e1· pla11ts also ft)r111s a 1)a1·t of 
tl1eir diet, as the3T a1"e r·atl1er common 111)on tl1e blossorr1s 
of pla11ts a11d fr11its. 

No accu1·ate estin1atio11 of t]1e valt1e of the ('.oleo1)te1·c1 
could be obtau1ecl wit.11011t i11cll1di11g· the Tele1)l101"idrP. Be­
sides Cha,uliog1zat:l i1ts pe,2 ·11 sylva1zic1ts :B1 01·st., ,,,,11ic11 l1c1s 
l)een fou11rl feeding lll)o11 t 11e larv~ of tl1e C(JJ'71JtJ·acl1el11<r:.· 
1rienupha1·· Hbst.,10 a11cl Telep1lio 11·21/, bilineat·lt.'3 Sc1:~, ,,., l1icl1 
is sucl1 a powerf11l a11xiliar)T i11 cl1eclring· tl1e 1·a,' c1.p;e::; of 
the wester11 locl1st,11 Pc>dal;1·,,s to111.e1itcJ,c;1.f.s Sa),. 11c1s l)0c)11 
observed f eec1i11g· llpon t 11 e cotto11 \\Too cl gall-licc1

, Pr' 111. ;Jll i­
gu s popitlivenae Fitc11, a11c1 t11e P. popi.f.Z·ic·<t1f'l'is Fitcl1. 
Tl1ese beetles sometimes 11la(·e tl1c1nsci,,es c1t t l 1r 01)011i11p; 

of the gall, occasio11a]l3r c1S 111a113T as f 0111· tog0tl1e1·, ,111(1 
catch the matt1r·e lice tts tJ1e>T c1tte1npt c111 c·g·1·css, ::111tl 

sometimes })lunge thei1· flat l1e;:1d and tl101·::lx i11tc) tl1c1 ril ,T_ 
ity and draw fortl1 a11cl d.e,,,ol11· lnrg·e c111cl s111al] i11<liR­
criminately. D111·ing tl1e latte1· }),t1·t of ,J1111r c111cl tl1~ fi1·st 
of July these l)eetles a1·0 vc1·)~ a1)l111c1a11t, 11<)t 0111)' tll)<)tl 

trees affected by gall-lice, b11t ll})<>Jt otl1c1· 1)l,111tR ,11R<). 

0 Am. Ent., Vol. II, p. 373. 
lU Am. Ent., Vol. I, pp. 35 ~tncl 51. 
11 Report U. S. Ent. Comm., Vol. I', p. 30 2. 


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