Effects of three host pine species on diapause induction and life-history traits of Monochamus alternatus alternatus (Coleoptera: Cerambycidae)

Figures & data

Table 1. Number, size and storage period of Pinus densiflora, P. thunbergii and P. echinata bolts used for rearing Monochamus alternatus alternatus larvae in each of three experiments

Exper-iment	Bolts used for rearing
	Pine species	Number of used	Length (cm)*	Diameter (cm)*	Period of bolt storage*^†
1	P. densiflora	50	15.0 ± 0.0	7.2 ± 0.3	52.1 ± 2.3
	P. thunbergii	48	15.0 ± 0.1	6.7 ± 0.3	50.1 ± 2.2
2	P. densiflora	31	15.1 ± 0.1	6.0 ± 0.2	30.0 ± 0.6
	P. thunbergii	45	15.0 ± 0.1	6.8 ± 0.3	24.1 ± 0.6
3	P. densiflora (J)^§	27	15.2 ± 0.1	3.9 ± 0.2	36.4 ± 1.0
	P. densiflora (K)^§	34	15.0 ± 0.1	8.3 ± 0.2	15.8 ± 0.7
	P. echinata (L)^§	42	14.9 ± 0.1	6.3 ± 0.4	59.0 ± 1.8

* mean ± SE.

^†Number of days from tree felling to larval inoculation

^§Letter in parentheses is used for identification of tree.

Table 2. Effects of Pinus densiflora, P. thunbergii and P. echinata bolts and insect sex on adult body mass, development time, ovariole number and food consumption for nondiapause individuals and incidence of diapause in Monochamus alternatus alternatus

Table 3. Analysis of variance tables for effects of experiment, pine species (Pinus densiflora and P. thunbergii), insect sex, bark surface area of bolt and period of bolt storage on adult body mass, development time and ovariole number in Monochamus alternatus alternatus (experiments 1 and 2)

Response variable	ANCOVA model*	Explanatory variables^†	F value	df	pvalue
Body mass	Full	P × B, P × R	< 0.687	1, 98	> 0.409
	Reduced	Experiment (E)	9.09	1, 100	0.003
		Pine species (P)	3.36	1, 100	0.070
		Insect sex (S)	0.78	1, 100	0.380
		Bark surface area (B)	2.26	1, 100	0.136
		Period of bolt storage (R)	2.95	1, 100	0.089
		P × E	7.20	1, 100	0.009
Development time	Full	P × B, P × R	< 0.395	1, 98	> 0.531
	Reduced	Experiment (E)	2.90	1, 100	0.092
		Pine species (P)	18.9	1, 100	< 0.001
		Insect sex (S)	2.07	1, 100	0.153
		Bark surface area (B)	5.24	1, 100	0.024
		Period of bolt storage (R)	5.12	1, 100	0.026
		P × E	8.57	1, 100	0.004
Ovariole number	Full	P × B, P × R	< 1.24	1, 51	> 0.270
	Reduced	Experiment (E)	0.47	1, 53	0.494
		Pine species (P)	0.18	1, 53	0.673
		Bark surface area (B)	0.19	1, 53	0.664
		Period of bolt storage (R)	0.29	1, 53	0.594
		P × E	1.74	1, 53	0.192

* Full ANCOVA (analysis of covariance) model included three interactions between experiment, pine species, bark surface area and period of bolt storage. When some interactions containing bark surface area or period of bolt storage showed no significant effects at the 5% significance level, reduced ANCOVA model excluding the interactions was used to determine the effects of explanatory variables. So, only insignificant interactions are described for explanatory variables in the full model in Table 3.

^†Cross indicates the interaction between explanatory variables.

Table 4. Analysis of variance tables for effects of tree (Pinus densiflora and P. echinata), insect sex and bark surface area of bolt on adult body mass, development time, ovariole number and food consumption in Monochamus alternatus alternatus (experiment 3)

Response variable	ANCOVA model*	Explanatory variables^†	F value	df	pvalue
Body mass	Full	Tree (T)	1.78	2, 78	0.175
		Insect sex (S)	0.02	1, 78	0.880
		Bark surface area (B)	35.3	1, 78	< 0.001
		T × B	5.41	2, 78	0.006
Development time	Full	Tree (T)	1.16	2, 78	0.318
		Insect sex (S)	0.20	1, 78	0.659
		Bark surface area (B)	19.5	1, 78	< 0.001
		T × B	3.46	2, 78	0.036
Ovariole number	Full	T × B	1.75	2, 39	0.188
	Reduced	Tree (T)	13.0	2, 41	0.846
		Bark surface area (B)	< 0.001	1, 41	0.990
Food consumption	Full	Tree (T)	3.76	2, 33	0.034
		Insect sex (S)	2.22	1, 33	0.146
		Bark surface area (B)	70.8	1, 33	< 0.001
		T × B	4.82	2, 33	0.015

* Full ANCOVA (analysis of covariance) model included the interaction between tree and bark surface area. When the interaction showed no significant effect at the 5% significance level, reduced ANCOVA model excluding the interaction was used to determine the effects of explanatory variables. So, only the insignificant interaction is described for explanatory variables in the full model in Table 4.

^†Cross indicates the interaction between explanatory variables.