Phylogeography of Organophosphate Resistant ace Alleles in Spanish Olive Fruit Fly Populations: A Mediterranean Perspective in the Global Change Context.

Esther Lantero,M Dolores Ochando,Susana Pascual,Beatriz Matallanas,Carmen Callejas

doi:10.3390/insects11060396

Abstract

The olive fruit fly (olf) Bactrocera oleae is the most damaging olive pest. The intensive use of organophosphates (OPs) to control it, led to an increase in resistance in field populations. This study assesses the presence and distribution of three mutations at the ace gene related to target site insensitivity to OPs in Spain. Samples from other Mediterranean countries were included as external references. Resistance-conferring alleles (from exons IV and VII of the ace gene) reached almost an 80% frequency in olf Spanish populations. In total, 62% of them were homozygous (RR/RR), this being more common in eastern mainland Spain. High frequencies of RR/RR individuals were also found in North Mediterranean samples. Conversely, in Tunisia, only sensitive alleles were detected. Finally, the exon X mutation ∆Q3 had an extremely low frequency in all samples. The high frequency of genotype RR/RR in Spain indicates high fitness in an agroecosystem treated with pesticides, in contrast to ∆Q3. At exon IV all flies carried the same haplotype for the allele conferring resistance. The sequence analysis at this exon suggests a unique origin and fast expansion of the resistant allele. These results provide evidence that OPs appropriate use is needed and prompt the search for alternative methods for olf pest control.

Highlights

Spain is the world’s leading producer and exporter country of table olives and olive oil [1].It concentrates more than 2.5 million ha of olive groves and 45% of the worldwide production [2,3].This trade implies about EUR 1.7 billion of annual benefits [4].The olive fruit fly, Bactrocera oleae (Rossi, 1790), is the most damaging olive pest
The Spanish olive fruit fly populations as a whole have a high frequency of SNP conferring resistance to organophosphates, both in IV and VII exons
The present analysis revealed 50% genetic resistance, mostly as heterozygosis (Figure 2), and a great diversity in the number of sensitive alleles at exon IV—seven, three of which were private

Summary

Introduction

Spain is the world’s leading producer and exporter country of table olives and olive oil [1].It concentrates more than 2.5 million ha of olive groves and 45% of the worldwide production [2,3].This trade implies about EUR 1.7 billion of annual benefits [4].The olive fruit fly (olf ), Bactrocera oleae (Rossi, 1790), is the most damaging olive pest. Spain is the world’s leading producer and exporter country of table olives and olive oil [1]. It concentrates more than 2.5 million ha of olive groves and 45% of the worldwide production [2,3]. This trade implies about EUR 1.7 billion of annual benefits [4]. The olive fruit fly (olf ), Bactrocera oleae (Rossi, 1790), is the most damaging olive pest. The B. oleae pest involves great economic costs in prevention and control of its populations

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