Distribution range shift of plant pests, possibly due to climate change: examples in

Junichi Yukawa

Kyushu University Japan 02’N) 02’N) ˚ ˚ ˚˚ 31’N) 31’N) ˚ ˚ ˚˚

Many armature Many have entomologists accumulated of records collection species insect various

The Japanese Japanese The extends Archipelago km 2,000 for about (24 from south There are 4 distinct are 4 distinct There a year in seasons to north (45 to north

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e e h T Benefits for studying northward range extensions of plant pests on the Japanese Archipelago Map of East Asia East Map of The number of alien pest species that have established in the Nansei Islands, Japan (including both natural invasion and accidental introduction)

Hymenoptera 81 spp. before 1980 Lepidoptera 8 spp. in the 1980s 17 spp. in 1990-2001 Diptera Coleoptera

Hemiptera Thysanoptera

Blattaria

Phasmida 0 10 20 30 40 Data indicate an increase of alien pest species from 81 The Nansei Islands to 106 in recent years About 250 butterfly species occur in Japan. At least 40 of them are exhibiting northward range extensions in recent years

Recently, 15 species newly arrived naturally and established on the Nansei Islands Papilio memnon, a pest of citrus trees, has extended its distribution rage in western

Established Collecting record 1940

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In 2000, P. memnon 500 km 1983 arrived in A case study: Distribution range shift of Nezara viridula and N. antennata

Both species are pests of various crops, such as rice, soybean, corn, tomato, eggplant, etc.

N. antennata is distributed in Japan, Korea, China, and southeastern Asian countries

N. viridula is distributed widely in the tropics, subtropics, and southern temperate zones In Japan, it was first recorded in 1874 and has been increasing since the 1950s in southwestern parts of Japan in association with the prevalence of early-planted rice Distribution of Nezara bugs in the Kii Peninsula

Tokyo Kyoto The Kii Peninsula Fukuoka

50 km Distribution map Osaka of N. viridua and N. antennata in the Kii Peninsula Wakayama in the 1960s Northern limit Arida N. viridula N antennata N. viridula was distributed along the Tanabe sea coast and south of Wakayama Shingu Kushimoto Distribution map Osaka Northern limit of N. viridua and In 2005 Kaiduka N. antennata in 70 km the Kii Peninsula Wakayama in 2005 Northern limit in the 1960s Arida Northern limit in the 1960s N. viridula N antennata

N. viridula was found in northern parts of Tanabe the Kii Peninsula Northern limit moved Shingu Kushimoto 70 km northward Distribution range shift of Nezara viridula in northern Kyushu and

Yamaguchi

Northern Kyushu Kyoto Tokyo Fukuoka Collecting records of N. viridula beforebefore and afterafter ● Yamaguchi 2007 Shimonoseki 20072000●

● Ikuhashi 2005 ● Usa 2004 Fukuoka 2003 ● ● Ogori 2004 ● Kurume 2002 ● Oita 2004 ● Ymae 2002 ● Tsukumi 2004 ● Saeki 1995 ● Ume 1967 ● Nobeoka 1960 ● Amakusa1965 30 km Amakusa1965 ● Takanabe 1957 N. viridula has extended its range northward also in northern Kyushu Changes in mean monthly temperature for January in northern Kyushu for 48 years from 1960 to 2007 10

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) 8 ℃ ℃ ℃ ℃ 7

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for January ( for January 4

Mean monthly teperature monthly Mean 3

2 1960 1970 1980 1990 2000

Since 1986, the temperature has exceeded 5 ˚˚˚C that is the lowest thermal limit for N. viridula to overwinter successfully. Previous, present, and future distribution range of Nezara viridula in Kyushu, Japan （（）■ ）

1960s 2005 2100

In red-colored areas , In 2005, temperature is N. viridula will cover a large mean temperature for about 1 ˚C higher than in area of Kyushu in 2100, if January exceeds 5 ˚C, the 1960s. Red-colored the temperature rises by allowing N. viridula to areas coincide well with 1.4 ˚C, which is the minimum overwinter successfully the actual range of N. prediction by Houghton et al . viridula in 2005 (2001) Interspecific mating occurs in the field between the two Nezara bugs

N. viridula has higher reproductive potential than N. antennata in terms of fecundity and the number of generations a year ( 3 in viridula , while 2 in antennata )

Interspecific mating caused a decline of N. antennata reducing the chance of intraspecific mating, resulted in the replacement of N. antennata by N. viridula in many places Ratio of N. viridula to N. antenna increased from 2002 to 2004

N. antennata

Buzen Usa

Oita Saganoseki Tsukumi 2002 2004

Saeki 80<

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Nobeoka N. viridula Sample size Summary of the case study

N. viridula has been extending its distribution range northward, possibly due to global warming The northern range limit of N. viridula is determined by the mean monthly temperature for January N. antennata has been replaced by N. viridula in many places as a result of interspecific competition. This is an indirect effect of climate change on the range shift of a congener. This study is a good example to indicate that climate change affects biodiversity In order to investigate and predict northward extensions of plant pests, we need to gather information about:

Detailed biological traits of the plant pests Distribution records in the past and present Factors limiting northward extension, such as (1) Cold hardiness in relation to winter temperature (2) Presence or absence of host plants, effective natural enemies, and competitors (3) Reproductive potential and ability of dispersal (4) Geographical barriers Thank you for your kind attention