Tl. Wilkinson et Ae. Douglas, APHID FEEDING, AS INFLUENCED BY DISRUPTION OF THE SYMBIOTIC BACTERIA - AN ANALYSIS OF THE PEA APHID (ACYRTHOSIPHON-PISUM), Journal of insect physiology, 41(8), 1995, pp. 635-640
Pea aphids (Acyrthosiphon pisum) whose symbiotic bacteria were disrupt
ed with the antibiotic chlortetracycline over the first 5 days after b
irth (i.e, aposymbiotic aphids), were able to feed from the host plant
Vicia faba, as indicated by the regular production of honeydew drople
ts and by electrical penetration graph (EPG) recordings of stylet pene
tration through the plant tissues to the sieve elements, No difference
was identified in the time taken by adult symbiotic and aposymbiotic
aphids [24 +/- 2.4 and 24 +/- 3.0 min (mean +/- SE), respectively] to
penetrate the plant tissues and puncture the sieve elements during the
probes which resulted in sustained phloem feeding, 7/8-day-old aposym
biotic larvae produced less honeydew (0.43 +/- 0.038 mg/aphid) over 24
h than symbiotic aphids (0.79) +/- 0.079 mg/aphid), but this differen
ce was attributed primarily to the greater body size of the symbiotic
aphids, suggesting that feeding by these larval aphids was not substan
tially impaired, The aposymbiotic larvae produced smaller honeydew dro
plets more frequently than symbiotic larvae, and no difference between
the number of droplets produced in the first and second 12 h in the 2
4 h recording period was found, Aposymbiotic adults, in contrast, fed
relatively poorly, Both EPG and honeydew production studies indicated
that all symbiotic adults, but only 60-66% of aposymbiotic adults, had
initiated phloem ingestion within a 10 h test period, It is proposed
that the deleterious effects of bacterial disruption may be cumulative
, and become increasingly severe and nonspecific with time since antib
iotic treatment, It is recommended that studies on the nutritional phy
siology of aposymbiotic aphids are conducted with recently-generated a
posymbionts, whose feeding responses are not impaired.