Bactrothrips brevitubus males guard egg-masses against predators and/or conspecific individuals until egg-hatching. The guarding males swung up and beat their abdomens each other when conspecific males approached to the guarded egg-masses. We introduced potential predators into the egg masses with/without guarding males to evaluate whether the guarding males could prevent the predation of eggs. The results showed that the survivals of egg masses with guarding males were higher than those without guarding males, suggesting the guarding behavior increases the offspring survivals. To evaluate whether the relatedness between egg-masses and guarding males could have an effect on the survival rates, we introduced potential predators into egg masses with related or non–related males. The results showed that the survivals of the egg masses with non–related males were not different from those with related males, suggesting that the relatedness does not have important effects on the guarding behavior. The females were more likely to oviposit their offspring on the dead leaves with more spores of Pestalotia spp. which helps larval development. These results suggest that the egg-masses guarding behavior of the male adults of this species could help to increase offspring survivorship, and might contribute to attract females to increase their mating opportunities.