This study investigated the temporal dynamics and environmental drivers of bark and ambrosia beetles (Curculionidae: Scolytinae and Platypodinae) in a tropical rainforest in Northern Borneo. Utilizing an extensive long-term dataset (2017–2020), we employed Multi-Taper Method (MTM) spectral analysis and lagged Path Analysis to decode the underlying structure of population fluctuations. To isolate true cyclical relationships and ensure statistical rigor, both climatic variables and insect capture data were rigorously detrended prior to the path analysis.Our results revealed a multi-scale periodicity, most notably a dual-significant 35-day cycle in Total Trap Capture (TTC). We propose that these short-term oscillations are fundamentally rooted in intrinsic generation cycles reflecting the developmental duration of individual insect species. Within this framework, the 35-day MJO acts primarily as a ”gatekeeper” rather than the sole driver, periodically providing resources through windthrow while modulating flight activity through rainfall inhibition. These dynamics are further governed by a hierarchy of ”ecological memory,” where climatic forcing at specific lags determines realized abundance. We identified two distinct sub-annual biological legacy tiers: a ~3-month lag representing a host-stress response pathway , and an ~8-month lag driven by the accumulation of multivoltine generations and the obligate incubation period required for fungal symbionts to degrade wood substrates.Based on these findings, we propose the Resonance Hypothesis, suggesting that intrinsic rhythms are phase-locked by intraseasonal pulses and modulated by multi-month biological legacies. These cycles are ultimately nested within supra-annual climatic modes, such as ENSO and the IOD, which dictate long-term population baselines. Our results suggest that the apparent stochasticity of tropical insects is an interference pattern created by these overlapping temporal rhythms.