Baverstock, J.

Brown, P.M.

Majerus, M.E.N.

Pell, J.K.

Roy, H.E.

Ware, R.L.

English

NERC Open Research Archive

INTERACTIONS BETWEEN HARMONIA AXYRIDIS AND TWO INSECT PATHOGENIC FUNGI  Roy HE1,2, Brown PM1,2, Ware RL3, Pell JK4, Baverstock J4 and Majerus MEN3  1Department of Life Sciences, Anglia Ruskin University, East Road, Cambridge CB1 1PT, UK; 2Biological Records Centre, Centre for Ecology and Hydrology-Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire, PE28 2LS, UK;  3Department of Genetics, Cambridge University, Downing Street, Cambridge, CB2 3EH, UK; 4Plant and Invertebrate Ecology Division, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK  Harmonia axyridis is a predatory coccinellid, native to central and eastern Asia.  It has been available in many countries for use as a biological control agent of pest aphids and scale insects.  In many of these countries, including the USA, H. axyridis has established. It is now considered an invasive alien species in many countries for a number of reasons including its impact on functional biodiversity.  In this paper we describe experiments conducted to assess the interactions between H. axyridis and two insect pathogenic fungi:  Pandora neoaphidis and Beauveria bassiana.  Pandora neoaphidis is an aphid-specific fungus and B. bassiana is a generalist insect pathogen known to be a natural mortality agent of overwintering ladybirds and is a potential candidate for the biological control of H. axyridis.  In this paper we explore ways in which these two pathogens interact with H. axyridis.  First we compare the susceptibility of three species of ladybird, H. axyridis, Coccinella septempunctata and Adalia bipunctata to Beauveria bassiana after exposure at three doses (105 (low), 107 (mid), 109 (high) spores per ml).  In addition we assessed the impact of B. bassiana on the fecundity of these three ladybird species.  Larvae of all species were highly susceptible to B. bassiana infection even at low doses.  In contrast adult Harmonia axyridis were extremely resistant to B. bassiana infection but even low doses reduced fecundity dramatically.  In comparison C. septempunctata and A. bipunctata adults were highly susceptible to B. bassiana even at mid and high doses but low doses did not result in significant mortality or reduce fecundity.  We discuss these results in relation to the potential for control of H. axyridis using B. bassiana.   Second we assessed the predation of the aphid-specific pathogenic fungus P. neoaphidis by H. axyridis collected from the UK (an invasive population) and Japan (a native population) relative to that of C. septempunctata and C. septempunctata subspecies brucki.  Overall, predation of uninfected aphids was greater than infected aphids and, when given a choice, a preference for aphids was shown.  However, H. axyridis (UK) consumed a greater quantity of fungal cadavers than C. septempunctata, C. septempunctata subspecies brucki and H. axyridis (Japan) and showed little preference for uninfected aphids over infected aphids.  Harmonia axyridis (UK) may, therefore, have an impact on the occurrence and persistence of P. neoaphidis.  The differences in intraguild predation by H. axyridis collected in the UK and those from Japan suggest that individuals that invaded the UK could have a different genetic profile to those in its native range. 

Interactions between Harmonia axyridis and two insect pathogenic fungi

http://nora.nerc.ac.uk/1133/1/RoyAphidophaga.pdf

Interactions between Harmonia axyridis and two insect pathogenic fungi

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