Ecological Dynamics of Two Seed Predators, Araecerus levipennis and Acanthoscelides macrophthalmus , on Leucaena leucocephala

ABSTRACT

Two seed predators,

Araecerus levipennis

Jordan and

Acanthoscelides macrophthalmus

(Schaeffer), exist in the invasive tree

Leucaena leucocephala

(Lam.) de Wit. This study aimed to understand interactions among
Ar. levipennis
,

A. macrophthalmus

and

L. leucocephala

in the invaded ecosystem. Bagging treatments were used to differentiate niches between the two seed predators. Results indicated niche partitioning between these seed predators as a guild;
Ar. levipennis
preferred early‐stage pods while

A. macrophthalmus

preferred late maturity stage pods. Logistic regression analysis of 401 pod samples with 64.3% single‐species occupation showed negative effects between species occurrence and heterospecific abundance (
Ar. levipennis
from 67% to 35% and

A. macrophthalmus

from 50% to 0%), suggesting interspecific competition.
Ar. levipennis
demonstrated priority effects, preempting resources at early maturity stages and competitively excluding

A. macrophthalmus

. Furthermore, early‐stage pods attacked by
Ar. levipennis
inhibited seed dispersal, triggering

L. leucocephala

to produce resin as a defence response. To understand the germination of predator‐attacked seeds, damaged seeds were collected to test germination and seedling survival. Seeds damaged by
Ar. levipennis
and

A. macrophthalmus

effectively reduced germination and seedling survival in the laboratory, but field observations revealed that

L. leucocephala

compensates through prolific seed production. This is the first comprehensive study documenting
Ar. levipennis
as a seed predator in the

L. leucocephala

system, highlighting the complex interactions between invasive plants and their seed predators. These findings demonstrate that single‐agent biocontrol is insufficient for effective management and highlight the necessity of biological control strategies that combine multiple control agents.