Environmental Entomology (2004) 33, 1192-1199

Charles Martins de Oliveira, João Roberto Spotti Lopes, Carlos Tadeu Dos Santos Dias and Lowell R. Nault (2004)
Influence of latitude and elevation on polymorphism among populations of the corn leafhopper, Dalbulus maidis (DeLong and Wolcott) (Hemiptera: Cicadellidae), in Brazil
Environmental Entomology 33 (5), 1192-1199
Abstract: Morphological variations in insects have been shown to be influenced by latitude and elevation. Here we show that these two parameters markedly influence the appearance of the corn leafhopper Dalbulus maidis (DeLong and Wolcott). Leafhopper samples were collected in maize from 27 localities in 10 Brazilian states, with latitudes from 5 to 28° S and elevations from 16 to 1,628 m. D. maidis was the only Dalbulus species found in the samples. Up to 10 males and 10 females of D. maidis from each collection site were evaluated for size, pigmentation, and body weight. Females were always bigger and heavier than the males in the same locality. For both sexes, there was a positive and significant correlation between the morphological variables measured and the latitude and elevation from where specimens were collected. Individuals from higher latitudes (southern region) were bigger, darker, and heavier than those from lower latitudes (northeastern region). There was also a tendency for an increase in body weight, head capsule width, and wing length at higher elevations.

Variações morfológicas em insetos podem ser influenciadas por latitude e elevação. Neste estudo nós mostrâmos que esses dois parâmetros influenciam marcadamente a aparência da cigarrinha-do-milho, Dalbulus maidis (DeLong and Wolcott). Cigarrinhas foram coletadas em milho em 27 localidades de 10 Estados brasileiros, com latitudes de 5 a 28°S e elevações de 16 a 1.628 m. D. maidis foi a única espécie de Dalbulus encontrada nas amostras. Examinaram-LC 10 machos e 10 fêmeas de D. maidis de cada local de coleta, quanto ao tamanho, pigmentação e peso do corpo. Fêmeas foram sempre maiores e mais pesadas que os machos em uma mesma localidade. Para ambos os sexos, houve uma correlação positiva e significativa entre as variáveis morfológicas avaliadas e a latitude e elevação de onde os espécimes foram coletados. Espécimes coletados em latitudes mais altas (região Centro-Sul) foram maiores, mais pigmentados e pesados do que aqueles de menores latitudes (região Nordeste). Houve também uma tendência de aumento do peso do corpo, largura da capsula cefálica e comprimento da asa em maiores elevações.
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Database assignments for author(s): Charles Martins de Oliveira

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Dalbulus maidis		Brazil (NE)
	Dalbulus maidis	Maize/corn (Zea mays)	Brazil (south)