Dear All,

Some years ago I consulted with Chinese colleagues and according to their report H. axyridis was not a nuisance in China. Regarding, references nobody mentioned - as far as I remember - it might have had some side-effects on original environment.

Hallo Peter,

No it's not considered a pest. But Adalia bipunctata, a European species now growing in abundance in Japan, is causing concern. One fo those funny things !

best, Andrew Davis

Similar to Coccinella septempunctata which is in Europe (still) a common and frequent species, but in the US an invasive species, causing concern too.

Dear Andrew and Peter,

Thanks very much for your answers! Apart from your answers, I received some "off-record" ones, where indeed the consensus seems to be that Harmonia is not considered a problem in their area of origin (but then again: one answer was: "but Japanese people like ladybirds", which points out that part of the answer might lie in the biological aspects, and part might also be a matter of differences in perception between inhabitants of different areas... But I am still hoping for some responses from China as well!

Dear All,

Some years ago I consulted with Chinese colleagues and according to their report H. axyridis was not a nuisance in China. Regarding, references nobody mentioned - as far as I remember - it might have had some side-effects on original environment.

Peter: In Argentina Harmonia axiridis was introduced as a predator of aphids, a function that performs better than native coccinellids due to its bigger size, higher consumption rate and high reproductive capacity. So it was considered a beneficial species, but some bad lateral aspects emerged later: It tends to displace native coccinellids, invades houses in winter, predates other aphids predators, like Sirphidae, and some dermic and respiratory allergies in humans have been reported. That’s why some investigators now think that their risks are more than the benefits, and discorauge its introduction.

Here you have some bibliography on the subject

Cottrell, T.E. 2004. Suitability of exotic and native lady beetle eggs (Coleoptera: Coccinellidae) for development of lady beetle larvae. Biological Control. 31: 362-371.

GOETZ, D.V. 2008. Harmonia axyridis ladybug invasion and allergy. Allergy Asthma Proc. 29(2):123-9.http://www.ncbi.nlm.nih.gov/pubmed/17291858

Koch, R.L. 2003. The multicolores Asian lady beetle, Harmonia axyridis: A review of the biology, uses in biological control and non-target impacts. J. Insect. Sci. 3: 1-16.

(http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=524671&blobtype=pdf )

Machado, A. 2006. El sarantontón asiático Harmonia axyridis (Pallas) presente en Canarias (Coleoptera: Coccinellidae). Vieraea 34:71-72.

(http://personal.telefonica.terra.es/web/machado10/pdf/entomology/synharmonia.pdf )

Saini, E.D. 2004. Presencia de Harmonia axyridis (Pallas) (Coleoptera: Coccinelidae) en la provincia de Buenos Aires. Aspectos biológicos y morfológicos. RIA 33(1): 151-160.

(http://www.inta.gov.ar/ediciones/ria/33_1/10.pdf )

SHARMA, K.; S.B. MULDOON; M.F. POTTER & H.L. PENCE. 2006. Ladybug hypersensitivity among residents of homes infested with ladybugs in Kentucky. Ann Allergy Asthma Immunol. 97(4): 528-31.

http://www.ncbi.nlm.nih.gov/pubmed/17291858

Dear Ricardo,

Thanks very much for your contribution, and all the references!! The things you describe have been experienced in North America and Europe, and it seems to be spreading to other continents as well, as demonstrated by your account; I also heard that Harmonia has been found in Africa; only Australia I am not sure about... But what really interests me also is whether Harmonia is also considered a nuisance or even pest in their area of origin. What I have heard so far, including within this discussion on Researchgate, is that this does not seem to be the case. This poses the question of whether this is due to the fact that in the area of origin Harmonia is to some extent controlled by its natural enemies, or, alternatively or additionally, the invasive populations have different properties from those in the area of origin? Contributions like yours, Ricardo, are very valuable to confirm that the negative impact of Harmonia in the invaded areas seems to be quite ubiquitous, which makes it even more urgent to find out how they are performing and experienced in their native areas....

Well if H. axyridis would have been considered as pest in its area of origin, the dudes that started to use and distribute this species to other continents as a beneficial, might had avoided this mistake then (but just a guess).

Anyway there are papers from Vilcinskas et al (Giessen, Germany) who found out that the populations of H. axyrids here contain a high number of microsporidia spores that might support the invasive capabilities, because if killed by other coccinellid species it's a lethal prey for them. Harmonia itself seems to have a resistance against these microsporidia.

This deadly load is a possible (and still controversial) addition to the other traits mentioned by Ricardo Garberoglio, which makes this species it a top predator in this guild.

Dear Peter,

Good point, of the unlikelihood of H. axy to be introduced elsewhere if it had already been a pest in the area of origin! On the other hand, it WAS already a pest in the USA, and yet they were introduced in Europe...

About your other point, Vilcinkas' paper: I know about this excellent work, but what I am still puzzled about is this: if indeed H. axy is the top predator (i.e. eats the others, rather than them, or their eggs being eaten), how would other, native ladybird species get infected with the microsporidia? See also our comment on Vilcinskas' paper in Science.

Dear Peter, the first point being a pest already in the US I didn't know, anyway AFAIK at that time in Europe no regulations existed about introduction of alien species, so they might just have ignored that problem...

And yes I read the comment, therefore I wrote this microsporidia issue seems still controversial. Anyway older C. septempunctata larvae or adults might feed on younger and smaller H. axyridis larvae. But surely the question is still open if the microsporidia are really important then for the invasive traits.

Concerning this invasive species issue, I'm not sure (or don't remember) if also some/many/all populations in the area of origin are infected, or if they just had bad luck to collect only a few infected from which the introduced populations worldwide stem from.

But the key question is "why is H. axyridis (HA, harlequin ladybird) problematic outside, but not inside, its original range in Asia. The mechanism or mechanisms have to be ones that accommodate this difference.

Microsporidia are unlikely to play a role because Vilcinkas et al. injected the microsporidia. Injection bypasses the gut and the gut inactivates the microsporidia when they are eaten. In any case, HA has these microsporidia in Asia too.

What we need is a mechanism is one that explains both the problems of HA outside Asia and the problems of Adalia bipunctata as an introduced species in Asia.

By the way, can we be careful about our terminology ? Being a 'pest', being 'invasive' and being 'introduced' are not the same things.

best, Andrew

Dear Andrew,

Your answers are very useful (and actually exactly what I was hoping to hear), but do you think that you could substantiate statements like "problems of Adalia as an introduced species in Asia" (I have never read anywhere that they actually cause problems there), and "the gut inactivates the microsporidia when they are eaten" (is there any literature supporting this?). Thanks for your active participation in this discussion!

Hallo Peter

Problems of Adalia bipunctata in Asia

... not eveything is necessarily published of course but i've worked in Japan for several years and have spoken to the lady bird researchers there. They see A. bipunctata as problematic.

Inactivation of Microsporidia

... this is covered in the large number of comments on Heiko's Science paper. The person to contact is of course John Sloggett in Maastricht.

best, Andrew

thanks so much Andrew! Of course I know you have been there for long; do you remember that we even met there in 2004?